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7,500 | Elevated temporal lability of myocardial repolarization after coronary artery bypass grafting. | Ventricular arrhythmias are uncommon after coronary artery bypass grafting (CABG), but the incidence and mortality are high in certain subsets of patients during the early recovery after surgery. Elevated temporal lability of myocardial repolarization has been associated with sudden cardiac death. The aim of the current study was to explore temporal variability of myocardial repolarization during both early and longtime follow-up after CABG.</AbstractText>Patients (n = 61) who had undergone CABG and healthy subjects (HS, n = 33) were examined. Electrocardiogram and beat-to-beat blood pressure were recorded at 5 weeks and 5 months after surgery. The QT variability index (QTVI) was calculated as the log ratio between the temporal variabilities of the QT and RR intervals. The QTVI and QT variances were elevated by 40% and 44%, whereas RR variances were reduced by 40% among patients 5 weeks after CABG compared to HS (-0.90 +/- 0.59, 29 +/- 30, and 1223 +/- 1895 ms(2) vs -1.50 +/- 0.29, 15 +/- 16, and 2200 +/- 2877 ms(2) for HS; P < .01 for all). The QTVI and QT variances decreased by 38% and 31% between 5 weeks and 5 months after CABG, whereas the RR variances increased by 51% (P < .01 for all). The QTVI values remained elevated among patients compared to HS at 5 months after CABG (P < .01), whereas QT and RR variances did not differ.</AbstractText>Elevated temporal lability of myocardial repolarization prevails particularly during the early recovery phase after CABG and may reflect increased susceptibility to ventricular arrhythmia.</AbstractText> |
7,501 | Aldosterone synthase gene polymorphism as a determinant of atrial fibrillation in patients with heart failure. | We analyzed the possible association between aldosterone synthase (CYP11B2) T-344C polymorphism, which is associated with increased aldosterone activity, and the prevalence of atrial fibrillation (AF) in 196 consecutive patients who had symptomatic systolic heart failure (HF; left ventricular ejection fraction <40%) for > or =3 months before recruitment. Genomic DNA was extracted from peripheral blood leukocytes using a standard protocol. Subjects were genotyped for the CYP11B2 polymorphism using the polymerase chain reaction/restriction fragment length polymorphism approach. AF was present in 63 patients (33%) with HF. We found the -344 CC genotype to be a strong independent marker for AF. Almost 1/2 (45%) of patients with this genotype had AF compared with 1/4 (27%) with -344 TT and TC genotypes (p = 0.01). A multivariate stepwise logistic regression model that included age, gender, New York Heart Association class, CYP11B2 -344CC genotype, and echocardiographic measurements of left ventricular ejection fraction, left atrial dimension, left ventricular end-diastolic diameter, and mitral regurgitation severity showed that the CYP11B2 CC genotype (adjusted for age and left atrial size) was an independent predictor of AF (adjusted odds ratio 2.35, 95% confidence interval 1.57 to 3.51, p = 0.03). In conclusion, CYP11B2 T-344C promoter polymorphism predisposes to clinical AF in patients with HF. |
7,502 | Case ascertainment and estimated incidence of drug-induced long-QT syndrome: study in Southwest France. | The aim of this study was to investigate the incidence and reporting rate of drug-induced long-QT syndrome (LQTS) in France [defined by evidence of torsades de pointes (TdP), QT prolongation and exposure to a relevant drug] and to assess feasibility of case collection for drug-induced LQTS.</AbstractText>A retrospective population-based study was carried out in Southwest France in five institutions: three main hospitals, one private clinic and one cardiac emergency unit, searched from 1 January 1999 to 1 January 2005 (population coverage of 614 000). The study population consisted of 861 cases with International Classification of Diseases-10 diagnostic codes for ventricular tachycardia (I147.2), ventricular fibrillation (I149.0) and sudden cardiac death (I146.1) from hospital discharge summaries, supplemented by cases reported to national or regional pharmacovigilance systems, and voluntary reporting by physicians, validated according to internationally defined criteria for drug-induced LQTS.</AbstractText>Of 861 patients coded with arrhythmias or sudden cardiac death, there were 40 confirmed surviving acquired cases of drug-induced LQTS. We estimated that the incidence of those who survive to reach hospital drug-induced LQTS is approximately 10.9 per million annually in France (95% confidence interval 7.8, 14.8).</AbstractText>Many cases of drug-induced LQTS may not survive before they reach hospital, as the reporting rate for drug-induced LQTS identified through the cardiology records and also reported to pharmacovigilance systems for the Midi-Pyrenees area is 3/40 (7.5%). Using the methods outlined it is possible to assemble cases to study genetic susceptibility to drug-induced LQTS and adapt these methods more widely.</AbstractText> |
7,503 | Risk of atrial fibrillation in dipper and nondipper sustained hypertensive patients. | The risk of atrial fibrillation (AF) in sustained hypertensive patients with different circadian blood pressure (BP) patterns is unknown. We investigated the risk of new onset AF in dipper and nondipper sustained hypertensive patients.</AbstractText>The occurrence of AF was evaluated in 1141 patients aged > or = 40 years with sustained hypertension (clinic BP > or = 140 and/or 90 mmHg and daytime BP > or = 135 and/or 85 mmHg). Among these patients, 783 had night-time systolic BP fall > or = 10% (dippers) and 358 had night-time BP decline <10% (nondippers).</AbstractText>During the follow-up (6.1+/-3.2, range 0.5-12.9 years), AF occurred in 43 patients. The AF rate per 100 patient-years in dippers and nondippers was 0.38 and 1.13, respectively. AF free survival was significantly different between the groups (P=0.0002). After adjustment for other covariates, including left atrial enlargement or left ventricular hypertrophy (these variables were analyzed in separate models because of a strong association between them) and 24-h BP, Cox regression analysis showed that the risk of AF was significantly higher in nondippers than in dippers [nondippers vs. dippers, relative risk (RR) 2.02, 95% confidence interval (CI) 1.08-3.79, P=0.028 in the model including left atrial enlargement, and RR 1.97, 95% CI: 1.05-3.69, P=0.035 in the model including left ventricular hypertrophy].</AbstractText>This study shows that nondipper sustained hypertensive patients have a two-fold greater risk of developing AF than dipper ones. This aspect could partly contribute to explain the higher cardiovascular risk previously observed in nondipper hypertensive patients.</AbstractText> |
7,504 | Attitudes toward automated external defibrillator use in Japan. | The American Heart Association 2005 Guidelines recommend immediate defibrillation for ventricular fibrillation (VF) of short duration, such as witnessed sudden cardiac arrest. However, it is unclear if public-access automated external defibrillators (AEDs) would actually be used in Japan, because there have been few studies about public attitudes regarding AED use. Therefore, we examined Japanese attitudes toward AED use.</AbstractText>Between February and March 2006, 3328 individuals, including high school students, teachers, emergency medical technicians (EMTs), medical nurses, and medical students, were asked about AED knowledge and their willingness to operate an AED. All EMTs, 86% of nurses, and 90% of medical students knew how to use AEDs, while only 15% of high school students and 44% of teachers had such knowledge. All EMTs, 78% of nurses, and 94% of medical students reported they would 'definitely' use the AED, but only 12% of high school students and 35% of teachers gave this reply. The reasons for unwillingness to operate AEDs among both laypeople and health care providers were poor of awareness of what AED is and/or how to use an AED. However, 83% of students and 81% of teachers with AED knowledge reported they would 'definitely' use the AED.</AbstractText>Many non-medical people in Japan would be unwilling to operate an AED, because they do not know what AED is and/or how to use an AED. However, many would be willing to operate AEDs if they had better understanding of AEDs. Thus, it is necessary to improve public knowledge of AEDs and AED use.</AbstractText> |
7,505 | [Left ventricular systolic function, paced QT dispersion, exercise tolerance and quality of life in long term follow up after ventricular pacemaker implantation (VVIR) and radiofrequency atrioventricular junction ablation in drug refractory atrial fibrillation]. | THE AIM OF THE STUDY was to analyze left ventricular systolic function and dimensions, paced QT dispersion (QTD), exercise tolerance (six minute walk test- M6) and quality of life (QOL) after RFAVJ in a 6-month (6m) and a 24-month (24m) follow-up.</AbstractText>RFAVJ was performed in 30 pts (18 men and 12 women) aged from 43 to 81 years (mean age 69.8+/-11.3). AF was first diagnosed from 2 to 9 (mean 5+/-2.1) years prior to ablation. All patients received VVIR pacemakers. Pacing rate was programmed at 80 bpm. Prior to RFAVJ all patients underwent: transthoracic echocardiography (ECHO) to assess the left ventricular ejection fraction (EF), ventricular end-diastolic and end-systolic dimension (LVDD, RVDD, LVSD, respectively) and left atrial dimension; QOL assessment based on self-evaluation using: a questionnaire of the SF-36, Manolis, DASI scale. M6 on flat surface. These examinations were repeated at 6m and 24m after ablation. The maximum QT interval (QTM), minimum QT interval (QTm) and QTD were measured from the 12-lead ECG after RFAVJ on the first day (1d) and at 6m, 24m following RFAVJ.</AbstractText>SF total increased from 73.4 to 96.3 (p < 0.0025) in 6m, and to 113.8 (ns) in 24m, symptomatic score from 15.7 to 20.8 (p < 0.025) in 6m, and to 22.4 (ns) in 24m, DASI from 39.3 to 46.1 (p < 0.01) in 6m and decreased to 23.9 (p < 0.001) in 24m. Any significant changes in EF and the remaining ECHO parameters in 6m were observed. At 24 m we found significant decreased in EF (p < 0.01) and increased in LVSD (p < 0.05). Parameters of the M6 significantly improved. A significant correlation was observed between the SF-36 and functional symptomatology and DASI in 6m. The mean QTm, QTM and QTD were unchanged.</AbstractText>1. In pts with drug refractory AF, RFAVJ and VVIR significantly improve QOL and M6. 2. At long term follow up a significant decrease in EF and increase in LVSD were demonstrated. 3. No significant changes in the paced QT and QTD were observed.</AbstractText> |
7,506 | Atrial fibrillation in heart failure: the chicken or the egg? | Atrial fibrillation (AF) and heart failure (HF) are the emerging epidemics of cardiovascular disease in the new millennium. Both are responsible for considerable morbidity and mortality and health budget expenditure. The advent of catheter ablation for patients with AF has provided important new insights into the relative contribution of AF to left ventricular dysfunction. The aim of this review is to discuss the complex interplay in the pathophysiology of AF and HF to improve our understanding of the basis for current treatment strategies and guide future research direction. |
7,507 | Endocardial transcatheter stimulation of the AV nodal fat pad: stabilization of rapid ventricular rate response during atrial fibrillation in left ventricular failure. | Recent acute studies demonstrated that atrioventricular (AV) node vagal stimulation during atrial fibrillation (AF) decreases the mean ventricular rate, thus improving hemodynamics.</AbstractText>We report a case of a woman with acute heart failure (HF), chronic AF with untreatable ventricular rapid response, in severe hypotensive state due to a cardiogenic shock. The patient underwent left ventricular (LV) pacemaker implantation and received 50 Hz AV node stimulation, delivered through a posteroseptal atrial lead, thus allowing a 100% pacing. Hemodynamics improvements allowed carvedilol titration; the rate was below 85 bpm after 4 days, then the atrial lead was removed.</AbstractText>This novel strategy may allow controlling the rapid AV response in patients undergoing pacemaker implantation.</AbstractText> |
7,508 | [ECG changes in alcoholic intoxication]. | Patients with acute alcohol intoxication often present with pathological electrocardiographic (ECG) changes. The changes are more frequent and prognostically more significant in chronic alcoholics, in patients with ischaemic heart disease (IHD), in alcohol cardiomyopathy or another organic heart disease, but they can also occur in young and healthy individuals. The typical ECG changes in inebriety are disturbances of heart rate having the nature of electric impulse generation disorder or of impulse conduction pathology. In persons without clinical evidence of heart disease, they are classified as 'holiday heart syndrome'. The most frequent tachyarrhythmia is atrial fibrillation; less frequent but prognostically much more significant is torsades de pointes (TdP) polymorphous ventricular tachycardia. Among bradyarrhythmias, the most significant is alcohol-induced sinus bradycardia which may be manifested by recurrent syncope. The higher the blood alcohol concentration, the higher the occurrence of a significant extension of ECG intervals with possible manifestation of latent conduction disturbance or even sudden cardiac death. Apart from heart rate disturbances, ECG picture very often shows non-specific repolarisation changes. Ischaemia, which is mostly asymptomatic in the form of silent myocardial ischaemia, is worsened in alcohol-intoxicated IHD patients. The resulting ECG may be to a large extent influenced by states which often associate with inebriety, such as hypothermia, hypoglycaemia or electrolyte imbalance. ECG changes similar to those due to acute alcohol intoxication are also present in acute abstinence syndrome, especially in delirium tremens. There is convincing evidence that not only chronic alcoholism, but also single episodes of excessive alcohol consumption are associated with increased cardiovascular mortality. |
7,509 | [Therapy of acute myocardial infarction in the prehospital setting]. | The time period from symptom onset to hospital admission is of outstanding importance for the prognosis of a patient with an acute myocardial infarction. He is threatened by sudden cardiac death triggered by ventricular fibrillation on the one hand and on the other hand this period offers the chance for a timely decision on the optimal reperfusion strategy. A broad spectrum of therapeutic opportunities regarding thrombolysis, antiplatelets and anticoagulation has been proven to be effective in large randomised trials and registries. These results should influence the individual decision on reperfusion treatment as well as the patient's conditions, time lines, logistics and local resources. |
7,510 | Angiotensin II receptor blockers and cardiovascular protection: focus on left ventricular hypertrophy regression and atrial fibrillation prevention. | Left ventricular hypertrophy (LVH) and atrial fibrillation (AF) are strong predictors of cardiovascular (CV) morbidity and mortality, independently of blood pressure levels and other modifiable and nonmodifiable risk factors. The actions of circulating and tissue angiotensin II, mediated by AT1 receptors, play an important role in the development of a wide spectrum of cardiovascular alterations, including LVH, atrial enlargement and AF. Growing experimental and clinical evidence suggests that antihypertensive drugs may exert different effects on LVH regression and new onset AF in the setting of arterial hypertension. Since a number of large and adequately designed studies have found angiotensin II receptor blockers (ARBs) to be more effective in reducing LVH than beta-blockers and data are also available showing their effectiveness in preventing new or recurrent AF, it is reasonable to consider this class of drugs among first line therapies in patients with hypertension and LVH (a very high risk phenotype predisposing to AF) and as adjunctive therapy to antiarrhythmic agents in patients undergoing pharmacological or electrical cardioversion of AF. |
7,511 | Biatrial anatomical reverse remodelling after radiofrequency catheter ablation for atrial fibrillation: evidence from real-time three-dimensional echocardiography. | Reports using two-dimensional echocardiography have indicated that radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) results in a reduction in the left atrial (LA) size. Furthermore, the effect of pulmonary vein isolation (PVI) on right atrial (RA) anatomical remodelling has not been studied. Three-dimensional echocardiography (3DE) allows us to more precisely quantify atrial volume. Our aim was to assess the effect of PVI on biatrial anatomical remodelling using real-time 3DE.</AbstractText>We prospectively studied 91 patients (age 59 +/- 8 years, 79 males) referred for RFCA of paroxysmal (n = 79) or chronic (n = 19) AF. Left atrial and RA volumes were measured using real-time 3DE at baseline and after 6 months of follow-up. Data on AF recurrences were also collected. Left atrial volume was significantly reduced at follow-up when compared with baseline (51 +/- 16 vs. 60 +/- 21 mL, P < 0.001). The same occurred with RA volume (43 +/- 17 vs. 50 +/- 20 mL, P = 0.001). The reduction in the LA volume was more marked in patients with chronic than in those with paroxysmal AF (17 +/- 16 vs. 6 +/- 17 mL, P = 0.017). Patients with AF recurrence (23%) showed similar atrial volume reduction compared with those who were seemingly cured.</AbstractText>Three-dimensional echocardiography shows evidence of biatrial anatomical reverse remodelling after RFCA for AF. A reduction in the atrial volume occurs despite recurrence of AF.</AbstractText> |
7,512 | Atrial Fibrillation and Heart Failure. | Atrial fibrillation is common in heart failure patients and is associated with increased mortality. Pharmacologic trials have not shown any survival benefit for a rhythm control over a rate control strategy. It has been suggested that sinus rhythm is associated with a survival benefit, but that the risks of anti-arrhythmic drug treatment and poor efficacy offset the beneficial effect. Catheter ablation for atrial fibrillation can establish sinus rhythm without the risks of anti-arrhythmic drug therapy. Data from randomized trials demonstrating a survival benefit for patients undergoing an ablation procedure for atrial fibrillation are still lacking. Ablation of the AV junction and permanent pacing remain a treatment alternative in otherwise refractory cases. Placement of a biventricular system may prevent or reduce negative consequences of chronic right ventricular pacing. Current objectives and options for treatment of atrial fibrillation in heart failure patients are reviewed. |
7,513 | Unoperated tetralogy of Fallot in a 68-year-old patient. | Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, generally treated with total correction within the first two years of life. Occasionally, some unoperated cases can reach older ages. A 68-year-old woman with diabetes mellitus presented with swelling in legs and abdomen, weakness, exertional dyspnea, and orthopnea. On physical examination, she had mild cyanosis with clubbing. Her blood pressure was 110/60 mmHg and pulse rate was 79 beat/min. She had a systolic ejection murmur and bilateral rales on basal lung areas. Massive edema was noted in both lower limbs. Electrocardiography showed atrial fibrillation with normal ventricular response. Chest radiography showed an increased cardiothoracic ratio and bilateral minimal pleural effusion. Echocardiography showed biatrial dilatation (right atrium 62 mm, left atrium 49 mm) and thickening of left ventricular walls. There was right ventricular hypertrophy with decreased systolic function. A very large ventricular septal defect and severe pulmonary stenosis were noted. The patient did not accept any interventional procedure. To our knowledge, this is the oldest unoperated TOF case reported from our country. |
7,514 | Evidence for benefits of angiotensin receptor blockade beyond blood pressure control. | Elevated levels of angiotensin II result in oxidative stress and endothelial dysfunction, which initiate atherogenic pathologic processes that are important in cardiovascular disease development. Angiotensin II induces its deleterious effects primarily through the type 1 receptor; these effects are inhibited by angiotensin II receptor blockers (ARBs) directly at the receptor level. Angiotensin II may potentiate protective mechanisms through stimulation of the type 2 receptor, which is not blocked by ARBs. Accumulating data suggest that blockade of angiotensin II production or activity provides vascular and cardioprotective benefits, such as reduction of atrial fibrillation, acute myocardial infarction, and heart failure events. Moreover, blockade of the renin-angiotensin system has been shown to offer renal protection in subjects with and without diabetes mellitus and to reduce the risk of new-onset diabetes. |
7,515 | Thyroid hormones suppress epsilon-PKC signalling, down-regulate connexin-43 and increase lethal arrhythmia susceptibility in non-diabetic and diabetic rat hearts. | We examined whether thyroid hormones affect myocardial epsilon-PKC signalling, downstream target substrate, connexin-43 (Cx43) and arrhythmogenesis in non-diabetic and diabetic rats. Diabetes was induced by a single streptozotocin injection (50mg/kg, i.v.). Triiodothyronine (T(3)) was applied by gavage (1microg/kg of body weight for 10 days) to 4 weeks and 9 weeks diabetic and age-matched non-diabetic rats. Western blot analysis of Cx43 and epsilon-PKC, immunofluorescence of Cx43, ultrastructure of cardiomyocytes and myocardial conduction velocity were performed. Isolated perfused heart preparation was used to test ventricular fibrillation susceptibility. T(3) significantly decreased epsilon-PKC expression in non-diabetic and suppressed in diabetic rat heart ventricles. Decline of epsilon-PKC signalling was associated with decrease of Cx43 phosphorylation in diabetic and to a greater extent in non-diabetic rat hearts. However, conduction velocity was significantly decreased in diabetic while enhanced due to T(3) and increased in non-diabetic T(3)-treated rat heart ventricles compared to non-treated. T(3)-induced down-regulation of Cx43 was associated with increased cardiac propensity to ventricular fibrillation. Findings indicate that activation of epsilon-PKC signalling linked with phosphorylation of Cx43 is one of the mechanisms involved in the adaptation of the heart to hyperglycemia. Suppression of epsilon-PKC and Cx43 phosphorylation by T(3) abolish benefit of adaptation rendering the heart prone to lethal arrhythmias. |
7,516 | Aborted sudden death from sustained ventricular fibrillation. | Ventricular fibrillation usually is sustained and unrelenting in human subjects and rarely is self-terminating after 30 seconds' duration. Temporal evolution of the arrhythmia in our patient suggested that organization of electrical activity varies over time. Interaction of organization with high catecholamine levels and hyperkalemia may play a role in self-termination of ventricular fibrillation. Understanding the true mechanisms of spontaneous defibrillation may provide newer therapeutic options for treatment of this otherwise fatal arrhythmia. |
7,517 | A high peak current 150-J fixed-energy defibrillation protocol treats recurrent ventricular fibrillation (VF) as effectively as initial VF. | We tested the hypothesis that the frequency of shock success differs between initial and recurrent episodes of ventricular fibrillation (VF).</AbstractText>Out-of-hospital cardiac arrest patients presenting with VF from December 1996 to February 2007 defibrillated using an AED with a fixed-energy protocol (150 J) (Philips Medical Systems, Seattle, WA) were included for analysis. We defined shock success as termination of VF within 5s post-shock (either asystole or organized rhythm). Generalized estimating equation (GEE) analysis was used to adjust for the interrelatedness of shocks within each patient.</AbstractText>One hundred and three events occurred during the study period. Patient characteristics included: mean age 64.4 years, 82.5% male, and 81.6% bystander witnessed. Synchronized call-to-shock time was 6.4+/-2.3 min (mean+/-S.D.). VF recurred in 64 (62.1%) patients. Two hundred and fifty-seven shocks delivered for initial (101) or recurrent (156) VF were available for analysis. Initial shocks terminated VF in 93/101 (92.1%); subsequent shocks terminated recurrent VF in 140/156 (89.7%). GEE odds ratio for shock type (initial versus refibrillation) was 1.10 (95% CI 0.37-3.24, p=0.87). After adjusting for potential confounders, shock type remained insignificant (OR 1.14, 95% CI 0.41-3.2, p=0.80). We observed no significant difference in ROSC (34.4% versus 46.2%, p=0.23) or survival (37.5% versus 41.0%, p=0.72) between those with and without VF recurrence.</AbstractText>We observed no significant difference in the frequency of shock success between initial and recurrent episodes of VF using this AED with a 150 J fixed-energy protocol. VF recurrence is common and does not adversely affect shock success, ROSC or survival.</AbstractText> |
7,518 | Palpitations in athletes. | In an athletic population, the incidence of palpitations varies from 0.3% to as high as 70%, depending on age and type of sport being studied. Palpitations, or an awareness of an increased or abnormal heart beat, are rare in the school-age athlete, but much more common in older endurance athletes. The majority are felt to be benign, with prognosis relating to type of specific rhythm disturbance and presence or absence of underlying heart disease. Atrial fibrillation can account for up to 9% of rhythm disturbances in elite athletes, and up to 40% in those with long-standing symptoms. In athletes with premature ventricular beats (PVCs), underlying heart disease is more likely to be present in those with a high PVC burden, defined as >/=2000 PVCs/24 hours. Choice of monitoring device is crucial in making a proper diagnosis of the specific rhythm disturbance. For symptoms occurring within a 24-hour period, simple Holter monitoring is adequate to make a diagnosis. However, if symptoms occur less frequently, clinicians must choose one of the other available monitoring devices. Most importantly, choice of device should depend on which device is most likely to detect the rhythm disturbance. Other cardiac testing such as echocardiography, stress testing, endomyocardial biopsy, genetic testing, electrophysiologic testing, or cardiac magnetic resonance imaging may be indicated as well. The majority of palpitations in athletes will be first identified by screening examination, or by a complaint from the athlete. The third and most current pre-participation examination monograph recommends asking the athlete if he/she has palpitations with exercise. The assumption has been made that palpitations occurring at rest in athletes are benign, but this theory has not been validated prospectively in a large cohort of the athletic population. Specific rhythms can often be treated with radiofrequency ablation, with return to sports provided there is no significant high risk underlying heart disease present. Athletes with known malignant ventricular rhythm disturbances, or underlying substrate for such, who have undergone implantation of an automatic implanted cardioverter-defibrillator are not recommended to return to sport because there is no data on the safety and efficacy of defibrillators in this clinical setting, and certain athletic activities may result in damage to the device. |
7,519 | Delayed protective effects of hyperoxia against cardiac arrhythmias and infarction in anesthetized rats. | Previous studies have shown that pretreatment with normobaric hyperoxia has cardioprotective effect in isolated rat heart. The present study was designed to test the hypothesis that pretreatment normobaric hyperoxia could induce delayed cardioprotection effect in an in vivo regional heart ischemia.</AbstractText>Experiment 1: Rats were exposed to normobaric normoxia or to normobaric hyperoxia (O(2) > 95%) for 15, 30, 60, 120, and 180 min (H15, H30, H60, H120, and H180 groups, respectively). After 24 h, they were subjected to 30 min regional ischemia and 90 min reperfusion. Then, the hearts were harvested for measurement of infarct size. Lead II of electrocardiogram was continuously recorded for analysis of ischemic arrhythmias. Experiment 2: Different oxygen concentrations were tested in the same model of heart ischemia.</AbstractText>Compared with normoxia group, infarct size significantly reduced in H120 and H180 groups (from 48.1 +/- 4 to 31.4 +/- 3.3 and 30 +/- 2.4, respectively); 120 and 180 min of >95% hyperoxia significantly reduced the number of ventricular beats (from 314 +/- 34.9 to 173 +/- 20.3 and 178 +/- 15.7, respectively) and incidence of ventricular fibrillation (from 66.8% to 30% and 22.2%, respectively). When the oxygen concentration decreased to 80%, its effect on infarct size was abolished; however, its antiarrhythmic effect persisted. Further reduction of oxygen concentration eliminated both the effects.</AbstractText>These results show that hyperoxia pretreatment may induce delayed anti-infarct and antiarrhythmic effects in anesthetized rats. These effects are dependent on the exposure time and oxygen concentration.</AbstractText> |
7,520 | Impact of pre-existing conditions, age and the length of cardiopulmonary bypass on postoperative outcome after repair of the ascending aorta and aortic arch for aortic aneurysms and dissections. | Repair of the ascending aorta and aortic arch carries a high morbidity and mortality, which can be complicated by the often emergent nature of the intervention.</AbstractText>We retrospectively evaluated the morbidity, mortality, and long-term survival in 101 patients who underwent repair of ascending aorta and aortic arch. Depending on the urgency of the operation, the patients were categorized as elective (EL, n=82) or emergent (EM, n=19). Log-rank-list and SPS were used to evaluate the data.</AbstractText>The average age was 58+/-16 years. The aortic diameter was 5.5+/-1 cm in the EL group and 6.1+/-1.4 cm for EM group. The aortic dissection in EL and EM groups was 15% and 79%, respectively. The mean circulatory arrest time (n=32 patients) was 38+/-18.5 min. The overall 30-day mortality was 4%: 0% for the EL group and 26% for the EM group. The overall 6-month mortality was 8%: 3.7% and 26% in EL and EM groups, respectively. Overall CVA was 3%: 0% in the EL group and 15.7% in the EM group. The mean CPB time was 176+/-81 min. The prolonged CPB time correlated with increased need for blood transfusion. The LOS was 12+/-8 days and correlated with increasing age (95% CI 0.06860-0.2307, P=0.0004), with NYHA stage of patients at the time of surgery (95% confidence intervals, 1.328-4.202, P=0.0003), with left ventricular ejection fraction (95% CI 0.2357 to -0.003029, P=0.0442) and with postoperative atrial fibrillation (95% CI 0.1192-0.4745, P=0.0018). The average ICU stay was 123+/-145 h. A prolonged CPB time resulted in extended ICU stay (95% CI 0.3655-1.486, P=0.0014). Further, the length of ICU stay correlated with NYHA status (95% CI 19.98-73.42, P=0.0008), age (95% confidence intervals 0.01668-3.761, P=0.0477), urgency of surgery (95% CI 65.00-124.0, P<0.0001), and length of CPB time (95% CI 0.3655-1.486, P=0.0014).</AbstractText>Emergent operations are associated with high morbidity and mortality. Pre-existing heart failure, advanced age, and prolonged cardiopulmonary bypass are associated with prolonged monitoring in the ICU.</AbstractText> |
7,521 | Short-long-short sequence caused by ventricular safety pacing inducing ventricular tachycardia in a patient with a dual-chamber implantable cardioverter defibrillator. | Ventricular safety pacing (VSP) is an algorithm used to prevent crosstalk inhibition and ventricular capture during the vulnerable period. We report a 78-year-old man with implantable dual-chamber defibrillator, in whom clusters of ventricular tachycardias (VTs) were provoked by the VSP. During rapid DDDR pacing, the delivery of the VSP after every other atrial-paced beat resulted in short-long-short ventricular sequences and induced VTs. An atrial-based lower rate timing, long atrioventricular pacing interval, and automatic gain control also accounted for this arrhythmogenic ventricular sequence. The VSP and the subsequent VT were eliminated by decreasing the pacing rate. |
7,522 | The impact of prehospital transport interval on survival in out-of-hospital cardiac arrest: implications for regionalization of post-resuscitation care. | There is growing evidence that therapeutic hypothermia and other post-resuscitation care improves outcomes in out-of-hospital cardiac arrest (OHCA). Thus, transporting patients with return of spontaneous circulation (ROSC) to specialized facilities may increase survival rates. However, it is unknown whether prolonging transport to reach a designated facility would be detrimental.</AbstractText>Data from OHCA patients treated in EMS systems that cover approximately 70% of Arizona's population were evaluated (October 2004-December 2006). We analyzed the association between transport interval (depart scene to ED arrival) and survival to hospital discharge in adult, non-traumatic OHCA patients and in the subgroup who achieved ROSC and remained comatose.</AbstractText>1846 OHCA occurred prior to EMS arrival. Complete transport interval data were available for 1177 (63.8%) patients (study group). 253 patients (21.5%) achieved ROSC and remained comatose making them theoretically eligible for transport to specialized care. Overall, 70 patients (5.9%) survived and 43 (17.0%) comatose ROSC patients survived. Mean transport interval for the study group was 6.9 min (95% CI: 6.7, 7.1). Logistic regression revealed factors that were independently associated with survival: witnessed arrest, bystander CPR, method of CPR, initial rhythm of ventricular fibrillation, and shorter EMS response time interval. There was no significant association between transport interval and outcome in either the overall study group (OR=1.2; 0.77, 1.8) or in the comatose, ROSC subgroup (OR 0.94; 0.51, 1.8).</AbstractText>Survival was not significantly impacted by transport interval. This suggests that a modest increase in transport interval from bypassing the closest hospital en route to specialized care is safe and warrants further investigation.</AbstractText> |
7,523 | Emergency laparoscopic surgery for complicated diverticular disease. | The aim of this study was to analyse the outcome of emergency laparoscopic surgical management of complicated diverticular disease.</AbstractText>A prospectively collected electronic database of all colorectal laparoscopic procedures between April 2001 and September 2007 has been used to identify outcomes in patients presenting with complicated diverticular disease.</AbstractText>Sixty-six patients (28 men), median age 69 years (23-95), ASA grade II (12), III (38), IV (16) have undergone emergency surgery for complicated diverticulitis--Hinchey grades I (27), II (29), III (7) and diverticular bleeding (3) over a 6(1/2)-year period: 43 high anterior resections, 17 Hartmann's resections and seven low anterior resections. Diverticular fistulas were seen in 16 patients: colovaginal (7), colovesical (2), colo-fallopian (4), entero-colic (3). The median operation time was 110 min (45-195 min). There was one conversion to open surgery. Postoperative analgesia was provided by intravenous Paracetamol in 33 patients (50%), patient-controlled analgesia in 24 (36%), oral Paracetamol and Oramorph (12%) and epidural opioid infusion (1.5%). The median time to normal diet was 24 h (4 h-6 days) and median hospital stay 5 days (2-30). There were two deaths (3.3%); anastomotic leak, ventricular fibrillation (VF) cardiac arrest. Other complications included: wound infection eight (12%), anastomotic leak four (8%), port-site hernia one and one case of Clostridium difficile colitis requiring colectomy. There were five (7.5%) returns to theatre and two readmissions (3%).</AbstractText>Laparoscopic resectional surgery in complicated diverticular disease is a feasible, safe and a largely predictable operation that allows for early hospital discharge and, in our opinion, improved patient care. We are encouraged to continue to offer our patients the option of an emergency laparoscopic resection.</AbstractText> |
7,524 | Use of a standardized order set for achieving target temperature in the implementation of therapeutic hypothermia after cardiac arrest: a feasibility study. | Induced hypothermia (HT) after cardiac arrest improved outcomes in randomized trials. Current post-cardiac arrest treatment guidelines advocate HT; however, utilization in practice remains low. One reported barrier to adoption is clinician concern over potential technical difficulty of HT. We hypothesized that using a standardized order set, clinicians could achieve HT target temperature in routine practice with equal or better efficiency than that observed in randomized trials.</AbstractText>After a multidisciplinary HT education program, we implemented a standardized order set for HT induction and maintenance including sedation and paralysis, intravenous cold saline infusion, and an external cooling apparatus, with a target temperature range of 33-34 degrees C. We performed a retrospective analysis of a prospectively compiled and maintained registry of cardiac arrest patients with HT attempted (intent-to-treat) over the first year of implementation. The primary outcome measures were defined a priori by extrapolating treatment arm data from the largest and most efficacious randomized trial: 1) successful achievement of target temperature for >or=85% of patients in the cohort and 2) median time from return of spontaneous circulation (ROSC) to achieving target temperature <8 hours.</AbstractText>Clinicians attempted HT on 23 post-cardiac arrest patients (arrest location: 78% out-of-hospital, 22% in-hospital; initial rhythm: 26% ventricular fibrillation/tachycardia, 70% pulseless electrical activity or asystole) and achieved the target temperature in 22/23 (96%) cases. Median time from ROSC to target temperature was 4.4 (interquartile range 2.8-7.2) hours. Complication rates were low.</AbstractText>Using a standardized order set, clinicians can achieve HT target temperature in routine practice.</AbstractText> |
7,525 | Iatrogenic circumflex coronary lesion in mitral valve surgery: case report and review of the literature. | Ischemic iatrogenic lesions can complicate surgical procedures on the mitral valve. One of the causative mechanisms is direct injury to or distortion of the circumflex coronary artery. The risk of damaging the circumflex coronary artery depends mainly upon the proximity of that vessel to the posterior segment of the mitral annulus, and this varies from patient to patient. Herein, we report a case of iatrogenic circumflex coronary artery lesion after mitral annuloplasty, and we review the literature on the subject, in order to highlight a possible relationship between iatrogenic circumflex lesions and coronary dominance. In a 60-year-old man who had severe mitral regurgitation due to prolapse of both leaflets, preoperative coronary angiography showed irregularities only along the left anterior descending coronary artery and a coronary network of right dominance. The patient underwent mitral annuloplasty (32-mm Carpentier-Edwards ring) by means of minimally invasive right thoracotomy through the right 4th intercostal space (HeartPort). When the procedure was over, and before the patient was taken to intensive care, ventricular fibrillation developed; the administration of direct-current shock (200 joules) resulted in a resumption of sinus rhythm. Repeat transesophageal echocardiography showed posterolateral dyskinesis of the left ventricle and ST-segment elevation suggestive of acute lateral myocardial infarction. Emergency cardiac catheterization revealed a subocclusion of the distal circumflex coronary artery. Dual percutaneous angioplasty and stenting (Taxus, 2.5 x 24 mm) was performed with optimal result. At the 1-year follow-up, the patient showed good results of the mitral annuloplasty. |
7,526 | Transvenous right ventricular pacing in a patient with tricuspid mechanical prosthesis. | We report a patient in whom permanent endocardial pacing was accomplished by passage of the electrode through a mechanical tricuspid valve. Echocardiography study showed a minimal tricuspid regurgitation. |
7,527 | Long-term follow-up of Tako-Tsubo-like syndrome: a retrospective study of 22 cases. | To assess the late outcome of the Tako-Tsubo like syndrome in a community hospital in northern Italy.</AbstractText>We reviewed 2233 patients who were admitted from 2001 to 2006 with diagnosis of acute coronary syndrome. Twenty-two patients (1%) presenting clinical and instrumental characteristics of Tako-Tsubo like syndrome were included in the study and prospectively underwent clinical and echocardiographic follow-up. All patients were women; aged 76 +/- 7 years; 82% experienced a stress before the acute episode; 50% reported chest pain and dyspnoea also days before. Mean troponin peak value was 3.6 +/- 3.3 microg/l. Mean acute echocardiographic ejection fraction was 40 +/- 7%. Eighteen percent of them presented major in-hospital complications. At a mean follow-up time of 27 +/- 19 months, 2 patients (9%) died because of ischemic stroke and renal failure, respectively, 14 (63%) were asymptomatic, 1 (5%) declared a paroxysmal episode of atrial fibrillation, and 5 (23%) still lamented dyspnoea or atypical chest pain. In all patients, typical apical ballooning disappeared and an increase in mean ejection fraction to 60 +/- 4% was observed.</AbstractText>After complications are promptly recognized and treated in the acute phase, prognosis of Tako-Tsubo like syndrome appears to be good at long-term follow-up, with a complete recovery of normal left ventricular function.</AbstractText> |
7,528 | Fatal QT interval. | A 21-year-old woman, without medical history, was admitted after cardiac arrest. Cardiopulmonary resuscitation and use of semiautomatic defibrillator quickly restored sinus rhythm. Clinical examination was normal with no cardiac murmur or abnormal heart sound. Electrocardiogram revealed sinus rhythm with short QT interval. Serum electrolytes and arterial blood gazes were normal. One hour after admission, lethal ventricular fibrillation occurred. Factors that shorten QT interval including increase in heart rate, hyperthermia, increased calcium, or potassium plasma levels and acidosis were excluded. Short-QT syndrome has been recently recognized as a genetic ion channel dysfunction leading to an abbreviation of action potential and a potential substrate for arrhythmias. This syndrome is characterized by a short QT interval (typically <320 milliseconds), associated with a high incidence of sudden death, syncope, or atrial fibrillation in individuals with an apparently normal heart. Implementation of an internal cardiac defibrillator remains the only effective preventive treatment. |
7,529 | Cardiac arrest in the setting of diet pill consumption. | The obesity epidemic currently plaguing the United States has spurred the development of a vast number of drugs to assist in the battle against obesity and its associated complications. The need to loose weight often causes patients to loose sight of or even ignore the serious side effects of some of the most widely used weight-loss medications. Here we present the case of ventricular tachycardia/fibrillation arrest in an otherwise healthy 48-year-old woman who was taking no medications other than phentermine, a common appetite suppressant that functions as a central nervous system stimulant through activation of the noradrenergic pathway of the sympathetic nervous system. |
7,530 | Bystander cardiopulmonary resuscitation for out-of-hospital cardiac arrest in the Hispanic vs the non-Hispanic populations. | The aim of this study is to compare rates of bystander cardiopulmonary resuscitation (CPR) for Hispanic and non-Hispanic out-of-hospital cardiac arrest (OOHCA) victims in Arizona.</AbstractText>This is a secondary analysis of consecutive OOHCA victims prospectively enrolled into our statewide OOHCA quality improvement database between November 2004 and November 2006. Continuous data are presented as means +/- SDs and analyzed using t tests; categorical data are presented as frequency of occurrence and analyzed using chi(2). The primary outcome was whether bystander CPR rates were different for Hispanic vs non-Hispanic OOHCA victims. Secondary comparisons were initial cardiac rhythms and survival to hospital discharge.</AbstractText>There were 2411 OOHCA victims during the period of analysis. A total of 952 arrests were excluded because ethnicity was not documented; 80 arrests were excluded because they were traumatic. A total of 1379 arrests were included for analysis, of which 273 (19.8%) were Hispanic. Hispanics were less likely to receive bystander CPR than non-Hispanics (32.2% vs 41.5%; P < .0001). Hispanics and non-Hispanics were dissimilar with respect to age (53.2 +/- 25 vs 64.5 +/- 19.3 years; P = .0001), paramedic response time (5.1 vs 5.5 minutes; P = .0006), initial rhythm asystole (53.8% vs 44.5%; P = .005), and initial rhythm ventricular fibrillation (20.5% vs 26.7%; P = .036). Survival to hospital discharge (8.1% vs 7.1%) was not statistically different.</AbstractText>In the state of Arizona, significantly fewer Hispanic OOHCA victims receive bystander CPR than non-Hispanics.</AbstractText> |
7,531 | Acute myocardial infarction with angiographically normal coronary arteries. | The authors present the case of a 51-year-old woman, with no known cardiovascular risk factors, admitted with anterior acute myocardial infarction complicated by primary ventricular fibrillation, who underwent reperfusion therapy with tenecteplase. Left heart catheterization on the sixth day showed left ventricular anteroapical akinesia and normal coronary arteries. The causes of acute myocardial infarction with normal coronary arteries and its differential diagnosis are discussed. |
7,532 | A fatal case of oleandrin poisoning. | The study presents a case of fatal poisoning with oleander leaves in an adult diabetic male. After repeated vomiting, and gastrointestinal distress the patient was admitted at the hospital with cardiac symptoms 1h after the ingestion. Urine samples were assayed immunochemically and by GC-MS for drugs of abuse and for general toxicological screen. Blood was analyzed for alcohol and volatiles by static head space GC-MS. Blood and oleander leaves were analyzed by LC-MS/MS for oleandrin and related compounds, the main cardiac glycosides of Nerium oleander. Oleandrin was detected by LC-MS/MS in the blood sample at a concentration of approximately 10 ng/ml. Another cardiac glycoside with pseudo-molecular ion of m/z 577, a likely structural isomer of oleandrin, was also detected in the blood and oleander leaves. However, by using the response as a function of concentration for oleandrin, this cardiac glycoside was roughly estimated at a concentration of approximately 10 ng/ml in the deceased blood. This would give a total fatal blood concentration of cardiac glycosides of about approximately 20 ng/ml in the deceased blood. |
7,533 | Lidocaine-induced Brugada syndrome phenotype linked to a novel double mutation in the cardiac sodium channel. | Brugada syndrome has been linked to mutations in SCN5A. Agents that dissociate slowly from the sodium channel such as flecainide and ajmaline unmask the Brugada syndrome electrocardiogram and precipitate ventricular tachycardia/fibrillation. Lidocaine, an agent with rapid dissociation kinetics, has previously been shown to exert no effect in patients with Brugada syndrome. We characterized a novel double mutation of SCN5A (V232I in DI-S4+L1308F in DIII-S4) identified in a rare case of lidocaine (1 mg/kg)-induced Brugada syndrome. We studied lidocaine blockade of I(Na) generated by wild-type and V232I+L1308F mutant cardiac sodium channels expressed in mammalian TSA201 cells using patch clamp techniques. Despite no significant difference in steady-state gating parameters between V232I+L1308F and wild-type sodium currents at baseline, use-dependent inhibition of I(Na) by lidocaine was more pronounced in V232I+L1308F versus wild-type (73.0+/-0.1% versus 18.23+/-0.04% at 10 micromol/L measured at 10 Hz, respectively). A dose of 10 micromol/L lidocaine also caused a more negative shift of steady-state inactivation in V232I+L1308F versus wild-type (-14.1+/-0.3 mV and -4.8+/-0.3 mV, respectively). The individual mutations produced a much less accentuated effect. We report the first case of lidocaine-induced Brugada electrocardiogram phenotype. The double mutation in SCN5A, V232I, and L1308F alters the affinity of the cardiac sodium channel for lidocaine such that the drug assumes Class IC characteristics with potent use-dependent block of the sodium channel. Our results demonstrate an additive effect of the 2 missense mutations to sensitize the sodium channel to lidocaine. These findings suggest caution when treating patients carrying such genetic variations with Class I antiarrhythmic drugs. |
7,534 | Acute and long-term efficacy and safety of catheter cryoablation of the cavotricuspid isthmus for treatment of type 1 atrial flutter. | Atrial flutter (AFL) is commonly treated by radiofrequency catheter ablation. Catheter-based cryoablation may be an effective alternative with potential advantages.</AbstractText>The purpose of this study was to study the acute and long-term safety and efficacy of catheter-based cryoablation for treatment of cavotricuspid isthmus-dependent (typical and reverse typical) AFL.</AbstractText>Catheter-based cryoablation was performed with a 10Fr catheter in 160 patients with cavotricuspid isthmus-dependent AFL (122 men and 38 women; mean age 63.1 +/- 9.3 years, mean left ventricular ejection fraction 54.6% +/- 10.4%); 94 (58.8%) of these patients also had atrial fibrillation (AF). All patients underwent right atrial (RA) activation mapping and pacing at the cavotricuspid isthmus to demonstrate concealed entrainment and confirm cavotricuspid isthmus dependence of AFL. Catheter-based cryoablation of the cavotricuspid isthmus was performed with multiple freezes (average freeze time 2.3 +/- 0.5 minutes) until bidirectional block was demonstrated during pacing from the low lateral RA and coronary sinus, respectively. Patients were evaluated at 1, 3, and 6 months and underwent weekly and symptomatic event monitoring. Acute procedural success was defined as cavotricuspid isthmus block persisting 30 minutes after ablation. Long-term success was defined as absence of AFL during follow-up.</AbstractText>Acute success was achieved in 140 (87.5%) of 160 patients. Total procedure time was 200 +/- 71 minutes, ablation time (including a 30-minute waiting period after ablation) was 139 +/- 62 minutes, and fluoroscopy time was 35 +/- 26 minutes. An average of 20.5 +/- 11.3 freezes, for a total ablation time of 47.4 +/- 24.3 minutes, were required to achieve cavotricuspid isthmus block, with average and nadir temperatures of -81.5 degrees C +/- 3.7 degrees C and -85.6 degrees +/- 3.6 degrees C, respectively. Four patients (2.5%) had procedure-related adverse events. Of 132 patients with acute efficacy who completed 6-month follow-up, 8 (6%) were lost to follow-up or were noncompliant with event recordings. Using survival analysis, 106 (80.3%) remained free of AFL on strict analysis of event recordings only, and 119 (90.2%) remained clinically free of AFL.</AbstractText>This large pivotal study demonstrated the acute and long-term efficacy and safety of catheter-based cryoablation for cavotricuspid isthmus-dependent AFL, similar to rates previously reported for radiofrequency catheter ablation.</AbstractText> |
7,535 | One-stage correction of aortic coarctation and severe mitral regurgitation via left posteriolateral thoracotomy in a 2-year-old child. | We successfully treated a case of a 2-year-old male with aortic coarctation coexisting with severe mitral regurgitation via left posteriolateral thoracotomy at one stage. After a mitral valve replacement under perfused ventricular fibrillation with moderate hypothermia, we repaired the aortic coarctation with coarctation resection and end-to-end anastamosis with the aid of deep hypothermic circulatory arrest and selective low-flow cerebral perfusion. The patient had an uneventful hospital course and remains well. |
7,536 | Atrial fibrillation due to late amiodarone-induced thyrotoxicosis. | A 60-year-old male patient complaining of palpitations, fatigue, weakness and weight loss of 1 month's duration was hospitalized in our cardiology department for atrial fibrillation. Thyroid function test results were compatible with thyrotoxicosis. The patient had been taking amiodarone for 2.5 years for hypertrophic obstructive cardiomyopathy and non-sustained ventricular tachycardia episodes. However, amiodarone had been discontinued after follow-up examinations revealed that the patient's ventricular arrhythmias were no longer present, and he had been taking metoprolol only for the preceding 6 months. In this patient, amiodarone-induced thyroiditis had developed 6 months after cessation of treatment, demonstrating that adverse effects may occur after discontinuation of amiodarone. Detection of the condition requires assessment of thyroid function before treatment initiation, during treatment and at regular intervals after treatment cessation. The type of hyperthyroidism induced by amiodarone cannot be determined in most cases. Patients with this condition should be referred to an experienced endocrinologist. Our case of delayed amiodarone-induced thryoiditis occcurred approximately 6 months after termination of amiodarone treatment. |
7,537 | Logarithm of the absolute correlations of the ECG waveform estimates duration of ventricular fibrillation and predicts successful defibrillation. | Measures of the ventricular fibrillation (VF) waveform may enable better allocation of cardiac arrest treatment by discriminating which patients should receive immediate defibrillation versus alternate therapies such as CPR. We derive a new measure based on the 'roughness' of the VF waveform, the Logarithm of the Absolute Correlations (LAC), and assess and contrast how well the LAC and the previously published scaling exponent (ScE) predict the duration of VF and the likelihood of return of spontaneous circulation (ROSC) under both optimal experimental and commercial-defibrillator sampling conditions.</AbstractText>We derived the LAC and ScE from two different populations--an animal study of 44 swine and a retrospective human sample of 158 out-of-hospital VF arrests treated with a commercial defibrillator. In the animal study, the LAC and ScE were calculated on 5s epochs of VF recorded at 1000 samples/s and then down sampled to 125 samples/s. In the human study, the LAC and ScE were calculated using 6s epochs recorded at 200 samples/s that occurred immediately prior to the initial shock. We compared the LAC and ScE measures using the Spearman correlation coefficients (CC) and areas under the receiver operating characteristic curve (AUC).</AbstractText>In the animal study, the LAC and ScE were highly correlated at 1000 sample/s (CC=0.93) but not at 125 samples/s (CC=-0.06). These correlations were reflected in how well the measures discriminated VF of < or =5 versus >5 min: AUC at 1000 samples/s was similar for LAC compared to ScE (0.71 versus 0.76). However AUC at 125 samples was greater for LAC compared to ScE (0.75 versus 0.62). In the human study, the LAC measure was a better predictor of ROSC following initial defibrillation as reflected by an AUC of 0.77 for LAC compared to 0.57 for ScE.</AbstractText>The LAC is an improvement over the ScE because the LAC retains its prognostic characteristics at lower ECG sampling rates typical of current clinical defibrillators. Hence, the LAC may have a role in better allocating treatment in resuscitation of VF cardiac arrest.</AbstractText> |
7,538 | Biphasic external defibrillation for adults in ventricular fibrillation or pulseless ventricular tachycardia. | Cardiac arrest, as a result of ventricular fibrillation or pulseless ventricular tachycardia, is a common phenomenon, and the only treatment available is defibrillation. Currently, defibrillators deliver either a monophasic or biphasic shock, depending on the device used. In 2005, the American Heart Association published new cardiac arrest management guidelines, which included directions about energy selection for both types of defibrillators. These guidelines created a platform to address misconceptions that exist in the practice setting with regard to the use of biphasic defibrillators. The purpose of this literature review was to highlight the issues related to the practical use of biphasic energy, including optimal energy selection and safety. |
7,539 | Obstructive sleep apnea and cardiovascular disease: role of the metabolic syndrome and its components. | Although obstructive sleep apnea and cardiovascular disease have common risk factors, epidemiologic studies show that sleep apnea increases risks for cardiovascular disease independently of individuals' demographic characteristics (i.e., age, sex, and race) or risk markers (i.e., smoking, alcohol, obesity, diabetes, dyslipidemia, atrial fibrillation, and hypertension). Individuals with severe sleep apnea are at increased risk for coronary artery disease, congestive heart failure, and stroke. The underlying mechanisms explaining associations between obstructive sleep apnea and cardiovascular disease are not entirely delineated. Several intermediary mechanisms might be involved including sustained sympathetic activation, intrathoracic pressure changes, and oxidative stress. Other abnormalities such as disorders in coagulation factors, endothelial damage, platelet activation, and increased inflammatory mediators might also play a role in the pathogenesis of cardiovascular disease. Linkage between obstructive sleep apnea and cardiovascular disease is corroborated by evidence that treatment of sleep apnea with continuous positive airway pressure reduces systolic blood pressure, improves left ventricular systolic function, and diminishes platelet activation. Several systematic studies are necessary to explicate complex associations between sleep apnea and cardiovascular disease, which may be compounded by the involvement of diseases comprising the metabolic syndrome (i.e., central obesity, hypertension, diabetes, and dyslipidemia). Large-scale, population-based studies testing causal models linking among sleep apnea, cardiovascular morbidity, and metabolic syndrome are needed. |
7,540 | Hypersensitivity to administered adrenaline in tetraplegia. | Case report.</AbstractText>To describe two clinical examples of denervation hypersensitivity, an enhanced response to catecholamines demonstrated experimentally in tetraplegic patients.</AbstractText>USA.</AbstractText>A 63-year-old man with chronic paralysis at C4 ASIA Impairment Scale (AIS) A with partial preservation to T6, and a history of coronary artery and pulmonary disease, developed bradycardia leading to cardiac arrest. He was treated with intravenous atropine 0.4 mg and adrenaline 1 mg. He regained consciousness and blood pressure within 30 s, but developed supraventricular tachycardia leading to ventricular fibrillation and death within minutes. The dose of adrenaline was routine for a cardiac arrest.A 60-year-old man with chronic paralysis at C6, AIS A, presented with fever to 106 degrees F and a renal stone. Thirty minutes after treatment with intravenous fluids, antibiotics, and 1 g aspirin orally, he became afebrile, then suddenly lost consciousness and palpable pulse. He recovered with equal rapidity after an intravenous injection of 0.1 mg adrenaline. The dose of adrenaline was a tenth the usual dose for cardiac arrest.</AbstractText>Because of denervation hypersensitivity, effective treatment of a cardiac arrest in tetraplegic patients may require a reduced dose of adrenaline.</AbstractText> |
7,541 | Aspirated air in the pericardial space during epicardial catheterization may elevate the defibrillation threshold. | A 79-year-old woman without structural heart disease underwent catheter ablation of ventricular tachycardia. Successful ablation was achieved on the left ventricular epicardium using an epicardial approach via pericardial puncture. Thereafter, programmed stimulation induced ventricular fibrillation (VF). A 360 J biphasic extrathoracic cardioversion using cutaneous pads in the conventional sternal-apical position failed to terminate the VF. After repositioning the sternal pad more laterally, the 360 J biphasic shock terminated the VF. Fluoroscopic imaging revealed aspirated air in the pericardial space, mainly apically. In this case, air aspirated into the pericardial space during the epicardial approach might have elevated the defibrillation threshold. |
7,542 | Comparison of a 10-breaths-per-minute versus a 2-breaths-per-minute strategy during cardiopulmonary resuscitation in a porcine model of cardiac arrest. | Hyperventilation during cardiopulmonary resuscitation (CPR) is harmful.</AbstractText>We tested the hypotheses that, during CPR, 2 breaths/min would result in higher cerebral perfusion pressure and brain-tissue oxygen tension than 10 breaths/min, and an impedance threshold device (known to increase circulation) would further enhance cerebral perfusion and brain-tissue oxygen tension, especially with 2 breaths/min.</AbstractText>Female pigs (30.4 +/- 1.3 kg) anesthetized with propofol were subjected to 6 min of untreated ventricular fibrillation, followed by 5 min of CPR (100 compressions/min, compression depth of 25% of the anterior-posterior chest diameter), and ventilated with either 10 breaths/min or 2 breaths/min, while receiving 100% oxygen and a tidal volume of 12 mL/kg. Brain-tissue oxygen tension was measured with a probe in the parietal lobe. The impedance threshold device was then used during an 5 additional min of CPR. During CPR the mean +/- SD calculated coronary and cerebral perfusion pressures with 10 breaths/min versus 2 breaths/min, respectively, were 17.6 +/- 9.3 mm Hg versus 14.3 +/- 6.5 mm Hg (p = 0.20) and 16.0 +/- 9.5 mm Hg versus 9.3 +/- 12.5 mm Hg (p = 0.25). Carotid artery blood flow, which was prospectively designated as the primary end point, was 65.0 +/- 49.6 mL/min in the 10-breaths/min group, versus 34.0 +/- 17.1 mL/min in the 2-breaths/min group (p = 0.037). Brain-tissue oxygen tension was 3.0 +/- 3.3 mm Hg in the 10-breaths/min group, versus 0.5 +/- 0.5 mm Hg in the 2-breaths/min group (p = 0.036). After 5 min of CPR there were no significant differences in arterial pH, PO2, or PCO2 between the groups. During CPR with the impedance threshold device, the mean carotid blood flow and brain-tissue oxygen tension in the 10-breaths/min group and the 2-breaths/min group, respectively, were 102.5 +/- 67.9 mm Hg versus 38.8 +/- 23.7 mm Hg (p = 0.006) and 4.5 +/- 6.0 mm Hg versus 0.7 +/- 0.7 mm Hg (p = 0.032).</AbstractText>Contrary to our initial hypothesis, during the first 5 min of CPR, 2 breaths/min resulted in significantly lower carotid blood flow and brain-tissue oxygen tension than did 10 breaths/min. Subsequent addition of an impedance threshold device significantly enhanced carotid flow and brain-tissue oxygen tension, especially in the 10-breaths/min group.</AbstractText> |
7,543 | Chronic ischemic mitral regurgitation induced in pigs by catheter-based coronary artery occlusion. | Ischemic mitral regurgitation (IMR) appears in 20-50% of patients after acute myocardial infarction, and entails an increased long-term mortality. In order to compensate for the diversified pathology in humans, this disease entity has been developed in pigs in order to allow investigations of therapeutic options against IMR.</AbstractText>The left circumflex coronary artery was occluded using catheter-based intracoronary coil deployment in 24 female pigs (body weight 50 kg). This was followed by a rapid pacing protocol. The left ventricular (LV) volumes at end-diastole and end-systole were assessed with multi-slice, short-axis cardiovascular magnetic resonance imaging. From these image sequences the mitral regurgitant volume (MRV) was quantified by subtracting the aortic flow volume from the LV stroke volume. The extension of myocardial infarction was quantified using a delayed contrast (gadolinium) enhancement technique. Five pigs served as controls.</AbstractText>During the procedure, seven animals died due to intractable ventricular fibrillation and technical problems. Eleven of the remaining 17 pigs fitted with coils survived the six-week follow up period. Of these animals, nine had a transmural inferior-lateral LV wall infarction and significant IMR (MRV = 10.5 +/- 6.3 ml). None of the control pigs had IMR. There was a positive correlation between the size of the myocardial infarction and the mitral regurgitant volume.</AbstractText>A catheter-based porcine model has been established for chronic IMR which balances between an adequate infarct size and acceptable mortality. The model provides a platform for further investigations of the geometric and hemodynamic features of chronic IMR in order to identify potential geometric targets of the disease. The model also allows the evaluation of innovative surgical approaches to reverse LV remodeling.</AbstractText> |
7,544 | Initial management of cardiac arrhythmias. | Diagnosis of acute arrhythmias requires recognition and interpretation of important electrocardiogram (ECG) findings, and knowledge of Australian resuscitation guidelines.</AbstractText>This article aims to provide a guide for general practitioners in managing patients who present with acute arrhythmias in the rural or regional setting.</AbstractText>Rural GPs need to be familiar with acute management of bradycardias, supraventricular tachycardia, atrial fibrillation and ventricular tachyarrhythmias, despite the fact that they may deal with these problems infrequently. A good local or regional network will help determine which patients can be treated locally, versus the need to refer to a hospital emergency department or outpatient setting. This might include a colleague reviewing an ECG sent by fax or email. Coronary care and emergency staff, both medical and nursing, have the expertise to participate collaboratively in such a network.</AbstractText> |
7,545 | Atrioventricular nodal ablation and biventricular pacing therapy with coronary venoplasty for severe heart failure with drug refractory atrial tachycardia. | A 53-year-old man was admitted to our hospital for dyspnea, associated with atrial tachycardia. He underwent mitral valve replacement and Maze operation for mitral regurgitation and atrial fibrillation and since then he suffered from drug refractory atrial tachycardia followed by cardiogenic shock with systolic heart failure. Atrial tachycardia with rapid ventricular response was medically refractory, and radical catheter ablation was thought to be very difficult due to post Maze operation, mitral mechanical valve replacement and unstable hemodynamics. Thus, atrioventricular nodal ablation, which was s safe procedure compared to the radical ablation for this patient, and biventricular pacemaker implantation, which required coronary venoplasty, were performed. Combination therapy may be one of the treatments for heart failure patients with drug refractory tachyarrhythmias. |
7,546 | Rhode Islanders' attitudes towards the development of a statewide genetic biobank. | To explore the attitudes of a voluntary subset of Rhode Island residents towards the potential development of a large, prospective, population-based study of sudden cardiac arrest, which will include a biobank to store blood for future biochemical and molecular analyses.</AbstractText>A mailed survey and focus groups.</AbstractText>Survey respondents and focus group participants indicated willingness to provide biospecimens, medical history and personal lifestyle information, and to undergo medical tests. Both datasets included multiple concerns regarding long-term storage of biospecimens and personal information, and the need of potential biobank participants for detailed information regarding study protocols and oversight.</AbstractText>A biobank has high potential for successful participant recruitment in Rhode Island if preceded by preparatory steps of public engagement and transparent mechanisms of addressing the population's concerns and questions.</AbstractText> |
7,547 | [How to treat arrhythmias in thoracic surgery]. | After major noncardiac thoracic operations, various types of arrhythmia would occur. Particularly atrial fibrillation (Af), have remained one of the most frequent complications. In the literatures, risk factors for post operative Af have identified age, male, extent of pulmonary resection and mediastinal lymph node dissection. When we would meet the patients complicated with arrhythmia, the etiology of it must be identified and treated before operations. If accidental arrhythmia occurred during or after operations, the etiology of arrhythmia as hypoxia, hypercapnea, electrolyte disorder, overhydration and cardiac ischemia would be checked and cleared at first. Then appropriate drugs should be considered to use due to the type of arrhythmia. In supraventricular tachyarrhythmia, especially Af, landiolol and verapamil would be effective for the rate control and disopyramide and procaineamide for the defibrillation. Lidocaine and propranolol would be an appropriate choice for ventricular tachyarrhythmia during operations. For ventricular tachyarrhythmia related with acute myocardial infarction, lidocaine and mexiletine would be proper. In bradyarrhythmias a temporary pacing should be the first choice for urgent therapy. A prompt assessment and an adequate therapy must be mandatory for the arrhythmias after major noncardiac thoracic operations. |
7,548 | Genetics of congenital long QT syndrome and Brugada syndrome. | The inherited cardiac arrhythmias including congenital and acquired long QT syndrome (LQTS), Brugada syndrome, progressive cardiac conduction defect, catecholaminergic polymorphic ventricular tachycardia, arrhythmogenic right ventricular cardiomyopathy, familial atrial fibrillation, familial sick sinus syndrome and short QT syndrome, are linked to mutations in genes encoding for ion channels or other membrane components. Eleven forms of congenital LQTS have been identified and these are caused by mutations in genes of the potassium, sodium and calcium channels or membrane adapter. Genotype-phenotype correlations have been rigorously investigated, especially in the LQT1, LQT2 and LQT3 forms, which constitute more than 90% of genotyped patients. On the other hand, causative mutations were identified much less in patients with Brugada syndrome, therefore data on genotype-phenotype relationships are limited. |
7,549 | Thrombus detection by echocardiography in patients with acute ischemic stroke and chronic or new-onset atrial fibrillation. | Recent articles have promoted anticoagulation for potential sources of embolism detected on echocardiography, despite lack of data regarding risk/benefit ratio for anticoagulating many of these abnormalities. Conversely, we have found echocardiography use in ambulatory stroke care to be of low yield. However, direct visualization of a thrombus might be considered a reasonable indication for anticoagulation. The current study assesses the use of transthoracic echocardiography (TTE) in thrombus detection in atrial fibrillation (AF) associated with acute stroke, which should present a good substrate for thrombus detection.</AbstractText>We conducted a chart review of patients admitted to our stroke department during a 6-month period, identifying and analyzing those with associated AF who were also submitted to TTE.</AbstractText>In all, 31 patients with AF (12 chronic and 19 new onset) were studied. TTE was conducted within approximately 60 +/- 41 hours. Thrombus was detected in only one patient with severe left ventricular dysfunction. Moderate to severe left ventricular function was detected in two additional patients with history of myocardial infarction. There were no other pertinent findings in 28 of 31 patients. All patients were anticoagulated on the basis of AF detection. Two died in hospital from stroke-related complications and 26 of 31 were discharged home or to rehabilitation.</AbstractText>TTE has a low yield of thrombus detection in patients with acute cardioembolic (AF-associated) stroke and has no impact on antithrombotic therapy in this patient population.</AbstractText> |
7,550 | [Amiodarone--still a useful antiarrhythmic drug]. | In former days, amiodarone was mainly used as high-dose prescription for serious ventricular arrhythmias. The indication was life-saving and a high incidence of adverse effects was consequently accepted. Such patients are currently protected by an implantable cardioconverter-defibrillator (ICD), and the typical amiodarone patient receives low-dose treatment for atrial fibrillation. In this situation, the tolerance for adverse effects is lower. Increased photosensitivity is often bothersome and the thyroid function is frequently affected. Cough and dyspnoe may still indicate drug-induced interstitial lung disease and is a feared complication that may have a lethal outcome, but it rarely occurs due to the lower doses prescribed. The pharmacokinetics of amiodarone are peculiar, and there are interactions with many drugs. Treatment must therefore be guided by a specialist of internal medicine or cardiology. Despite these limitations, amiodarone is a useful drug, both in the emergency setting and in the atrial fibrillation patients who respond poorly to conventional treatment. Amiodarone may prove beneficial in the primary prevention of atrial fibrillation, to convert fibrillation, to prevent recurrency, and finally, to reduce a fast ventricular rate that does not respond to standard therapy. |
7,551 | Chemical ablation of the Purkinje system causes early termination and activation rate slowing of long-duration ventricular fibrillation in dogs. | Endocardial mapping has suggested that Purkinje fibers may play a role in the maintenance of long-duration ventricular fibrillation (LDVF). To determine the influence of Purkinje fibers on LDVF, we chemically ablated the Purkinje system with Lugol solution and recorded endocardial and transmural activation during LDVF. Dog hearts were isolated and perfused, and the ventricular endocardium was exposed and treated with Lugol solution (n = 6) or normal Tyrode solution as a control (n = 6). The left anterior papillary muscle endocardium was mapped with a 504-electrode (21 x 24) plaque with electrodes spaced 1 mm apart. Transmural activation was recorded with a six-electrode plunge needle on each side of the plaque. Ventricular fibrillation (VF) was induced, and perfusion was halted. LDVF spontaneously terminated sooner in Lugol-ablated hearts than in control hearts (4.9 +/- 1.5 vs. 9.2 +/- 3.2 min, P = 0.01). After termination of VF, both the control and Lugol hearts were typically excitable, but only short episodes of VF could be reinduced. Endocardial activation rates were similar during the first 2 min of LDVF for Lugol-ablated and control hearts but were significantly slower in Lugol hearts by 3 min. In control hearts, the endocardium activated more rapidly than the epicardium after 4 min of LDVF with wave fronts propagating most often from the endocardium to epicardium. No difference in transmural activation rate or wave front direction was observed in Lugol hearts. Ablation of the subendocardium hastens VF spontaneous termination and alters VF activation sequences, suggesting that Purkinje fibers are important in the maintenance of LDVF. |
7,552 | Minimal invasive mitral valve repair for mitral regurgitation: results of 1339 consecutive patients. | Some have expressed concern that minimal invasive mitral valve (MV) repair may not meet the standard of open surgical techniques. We therefore reviewed our results for minimal invasive MV repair for mitral regurgitation (MR).</AbstractText>Between March 1999 and February 2007, a total of 1536 consecutive patients underwent minimal invasive MV surgery for MR at our institution using a right lateral mini-thoracotomy and femoral cannulation for cardiopulmonary bypass. Of these, a total of 1339 (87.2%) patients underwent MV repair and these form the focus of this study. The mean grade of preoperative MR was 3.3+/-0.6, age was 60.3+/-12.7 years, ejection fraction was 59.2+/-15.1% and 819 patients (61.2%) were male.</AbstractText>The procedure was successfully performed in all but four patients (0.3%) who required intraoperative conversion to full sternotomy. MV repair techniques consisted of ring annuloplasty with or without chordae-replacement or Carpentier-type leaflet resection. Concomitant procedures consisted of atrial fibrillation ablation in 351 patients (26.2%), tricuspid valve surgery in 80 patients (6.0%), and patent foramen ovale/atrial septal defect closure in 88 patients (6.6%). Mean duration of CPB was 121+/-38min and mean aortic cross-clamp time was 70+/-32min. Thirty-day mortality was 2.4%. Follow-up was performed in 99% of patients at an average of 28.1+/-23.9 months postoperatively. The Kaplan-Meier estimate for survival at 5 years was 82.6% (95% CI: 78.9-85.7%) and for freedom from MV reoperation was 96.3% (95% CI: 94.6-97.4%).</AbstractText>Minimal invasive MV repair, along with certain concomitant procedures, can be performed in the vast majority of patients with MR. Our large series demonstrates that these procedures can be performed with low perioperative complication rates and very good durability.</AbstractText> |
7,553 | Impact of different compression-ventilation ratios during basic life support cardiopulmonary resuscitation. | The 2005 revised guidelines for cardiopulmonary resuscitation (CPR) suggest a universal compression-to-ventilation (C:V) ratio of 30:2. The effects of this ratio in a realistic CPR scenario have not been investigated completely.</AbstractText>After 4 min of untreated ventricular fibrillation (VF), 24 pigs were randomly assigned to 6 min of basic-life support (BLS) CPR with 21% oxygen, and either (1) chest compressions only ("CC" group, n=8), or (2) cycles of 30 compressions followed by two breaths with a self-inflating bag (Fio2 0.21, C:V ratio 30:2; "30:2" group, n=8), or (3) 15 compressions followed by two breaths (C:V ratio 15:2; "15:2" group, n=8), all followed by advanced life support.</AbstractText>Arterial PO2 during BLS-CPR was higher in the 15:2 group compared to the 30:2 and CC groups (74+/-3 vs. 59+/-2 and 33+/-4 mmHg, respectively; p<0.05). Both mixed-venous PO2 and SO2 were higher in the 15:2 and 30:2 groups, compared to the CC group ( PO2 : 23+/-2 and 25+/-1 vs. 17+/-1 mmHg; SO2: 21+/-6 and 19+/-3 vs. 8+/-1 %, respectively; p<0.05). Arterial pH decreased in the 30:2 and CC groups compared to the 15:2 group (7.33+/-0.03 and 7.25+/-0.02 vs. 7.51+/-0.04, respectively; p<0.001). 4/8, 2/8, and 0/8 animals in the 15:2, 30:2, and CC groups, respectively, had ROSC at the end of the study period (p=ns).</AbstractText>Increasing the chest compression ratio from 15:2 to 30:2 resulted in changes in arterial, but not mixed-venous, blood gases; therefore, the advantages of more chest compressions may outweigh a decrease in gas exchange.</AbstractText> |
7,554 | Support vector machine-based arrhythmia classification using reduced features of heart rate variability signal. | This paper presents an effective cardiac arrhythmia classification algorithm using the heart rate variability (HRV) signal. The proposed algorithm is based on the generalized discriminant analysis (GDA) feature reduction scheme and the support vector machine (SVM) classifier.</AbstractText>Initially 15 different features are extracted from the input HRV signal by means of linear and nonlinear methods. These features are then reduced to only five features by the GDA technique. This not only reduces the number of the input features but also increases the classification accuracy by selecting most discriminating features. Finally, the SVM combined with the one-against-all strategy is used to classify the HRV signals.</AbstractText>The proposed GDA- and SVM-based cardiac arrhythmia classification algorithm is applied to input HRV signals, obtained from the MIT-BIH arrhythmia database, to discriminate six different types of cardiac arrhythmia. In particular, the HRV signals representing the six different types of arrhythmia classes including normal sinus rhythm, premature ventricular contraction, atrial fibrillation, sick sinus syndrome, ventricular fibrillation and 2 degrees heart block are classified with an accuracy of 98.94%, 98.96%, 98.53%, 98.51%, 100% and 100%, respectively, which are better than any other previously reported results.</AbstractText>An effective cardiac arrhythmia classification algorithm is presented. A main advantage of the proposed algorithm, compared to the approaches which use the ECG signal itself is the fact that it is completely based on the HRV (R-R interval) signal which can be extracted from even a very noisy ECG signal with a relatively high accuracy. Moreover, the usage of the HRV signal leads to an effective reduction of the processing time, which provides an online arrhythmia classification system. A main drawback of the proposed algorithm is however that some arrhythmia types such as left bundle branch block and right bundle branch block beats cannot be detected using only the features extracted from the HRV signal.</AbstractText> |
7,555 | Relationship between amiodarone-induced subclinical lung toxicity and Th1/Th2 balance. | Although amiodarone is a potent antiarrhythmic agent, its clinical use is limited by serious lung toxicity. This study investigated the mechanisms of amiodarone-induced lung toxicity from an immunological perspective. Because interferon gamma (IFN-gamma: Th1 cytokine) inhibits pulmonary fibroblast proliferation whereas interleukin-4 (IL-4: Th2 cytokine) augments fibroblast growth and collagen production, we hypothesized that amiodarone lung toxicity is related to Th1/Th2 balance.</AbstractText>Twenty-six consecutive Japanese patients with ventricular arrhythmias treated with amiodarone were enrolled in this study and were divided into two groups. Group A contained patients demonstrating amiodarone lung toxicity diagnosed by chest X-ray, KL-6 or D(LCO) (n=6), whereas group B included patients treated without any adverse effects (n=20). Th1/Th2 balance was investigated by the ratio of IFN-gamma and IL-4 produced by activated peripheral CD4(+) T cells.</AbstractText>Clinical baseline characteristics prior to oral amiodarone did not show any differences between group A and group B except for D(LCO) (82.0+/-5.2% vs. 90.8+/-9.0%, p=0.032) and Th1/Th2 balance (7.98+/-1.68 vs. 13.34+/-5.10, p=0.020). This balance was not altered three months after withdrawal of amiodarone in group A and under continued treatment in group B, suggesting patient-specific rather than amiodarone-induced. After starting amiodarone, serum concentration of desethylamiodarone was greater in group A than in group B (p=0.009) and was inversely proportional to Th1/Th2 ratio (p=0.013). Multilogistic regression analysis indicated that Th1/Th2 balance was the most powerful indicator of amiodarone lung toxicity (p=0.046, odds ratio of 0.424).</AbstractText>Although large cohort is required, the present study indicates that Th1/Th2 balance may influence amiodarone metabolism and may be a powerful indicator of amiodarone-induced subclinical lung toxicity at least in Japanese.</AbstractText> |
7,556 | Delayed anti-arrhythmic effect of nitroglycerin in anesthetized rats: involvement of CGRP, PKC and mK ATP channels. | Delayed anti-infarct and anti-stunning effects of nitroglycerin (NTG) have well been established in some animal models. The main goals of this study in anesthetized rats were to determine whether NTG has a delayed anti-arrhythmic effect and if so, whether calcitonin gene-related peptide (CGRP), protein kinase C (PKC) and mitochondrial K(ATP) channels (mK(ATP)) are involved in triggering this response. For this purpose, on day 0, male Wistar rats received NTG (120 microg/kg, iv) with or without pre-administration of PKC inhibitor chelerythrine (CHE), capsaicin (CAP) to deplete CGRP from sensory nerves or mK(ATP) channel blocker 5-hydroxydecaonic acid (5HD). On day 1, their hearts were subjected to 30 min ischemia and 120 min reperfusion. In rats pretreated with NTG, the incidence of ventricular tachycardia and ventricular fibrillation and the mortality rate significantly reduced (from 100%, 61% and 18.1% in the control group to 45.4%, 10% and 0% in the NTG group, respectively). Infarct size also reduced from 58+/-4.7% in the control group to 31+/-3.7% in the NTG group. These effects were abolished by CHE, CAP and 5HD, which none of them alone had any effect on infarct size or the incidence of myocardial arrhythmias. These results show that a low dose of NTG has a delayed anti-arrhythmic effect and this effect may share a common mechanism with anti-infarct effects of this drug, involving CGRP release and PKC and mK(ATP) activation. |
7,557 | Establishing Arizona's statewide cardiac arrest reporting and educational network. | Only a few large cities have published their out-of-hospital cardiac arrest (OHCA) survival statistics using the Utstein style reporting method. To date, to the best of our knowledge there has been no published OHCA survival data for a state.</AbstractText>To describe the process, benefits, and challenges of establishing a statewide OHCA database and educational network.</AbstractText>Arizona's Bureau of Emergency Medical Services and Trauma System initiated a statewide, prospective, observational cohort review of all OHCA victims on whom resuscitation was attempted in the field. Emergency medical services (EMS) first care reports, voluntarily submitted by 35 departments in Arizona, were analyzed. We chronicled the development of our data-collection process along with how we obtained patient outcomes and delivered feedback to field providers. Entry data included time intervals and nodal events conforming to the Utstein style template.</AbstractText>In data collected between January 1, 2005, and April 1, 2006, there were 1,484 OHCAs reported, of which 1,104 were of presumed cardiac etiology occurring prior to EMS arrival. The OHCA incidence was approximately 0.44 per 1,000 population per year. In our database, bystander CPR provided an odds ratio of 3.0 for survival (95% confidence interval 1.3, 6.7). Outcomes for 1,076 patients were obtained. Thirty-seven (3.4%) of the 1,076 cardiac arrest victims survived to hospital discharge. Twenty-seven (8.6%) of the 331 ventricular fibrillation cardiac arrest victims survived to hospital discharge.</AbstractText>It is feasible for a public health agency to implement a voluntary, statewide data-collection system and educational network to determine and improve survival from OHCA.</AbstractText> |
7,558 | The effect of adenosine A1 receptor antagonism on return of spontaneous circulation and short-term survival in prolonged ventricular fibrillation. | Endogenous adenosine (ADO) is cardioprotective during ischemia and its myocardial concentration increases during untreated ventricular fibrillation (VF). We have previously shown that ADO A1 receptor (ADOA1R) antagonism hastens the time-dependent decay in VF waveform morphology during the circulatory phase of cardiac arrest.</AbstractText>To determine the effect of ADOA1R antagonism on ROSC and short-term survival in prolonged VF.</AbstractText>Thirty-six swine were assigned by block randomization to one of three groups: a group that received only vehicle (CONTROL), an ADOA1R antagonist pretreatment group (PRE), and a group that was given ADOA1R antagonist during resuscitation (DURING). The animals were instrumented under anesthesia, and ADOA1R antagonist or vehicle, per group assignment, was infused 5 minutes prior to VF induction. At minute 8 of untreated VF, chest compression with ventilation was initiated and a standard drug cocktail, with ADOA1R antagonist or vehicle, was given. The first rescue shock (150 J biphasic) was delivered after 11 minutes of VF. Proportions with 95% confidence intervals (CIs) were calculated for the two outcome measures.</AbstractText>The baseline characteristics and chemistry values for the three groups were mathematically the same. The DURING group had a greater proportion of female animals (seven of 12) in comparison with the CONTROL group (two of 12) (p=0.03). ADOA1R antagonism hastened the decay of VF as previously demonstrated, but the rate of ROSC was the same for all groups: CONTROL=seven of 12, PRE=six of 12, and DURING=seven of 12. There were also no differences in short-term survival: CONTROL=four of 12, PRE=five of 12, and DURING=seven of 12.</AbstractText>In this study, ADOA1R antagonism had no effect on outcome whether given before induction of VF or upon resuscitation after 8 minutes of untreated VF. The role of endogenous ADO in prolonged VF remains unclear.</AbstractText> |
7,559 | Derivation of clinical predictors of failed rescue shock during out-of-hospital ventricular fibrillation. | Failed rescue shocks have been shown to decrease the likelihood of survival in the treatment of out-of-hospital ventricular fibrillation (VF). Avoidance of failed shocks may improve survival.</AbstractText>We sought to derive clinical predictors that could be used by emergency medical services (EMS) personnel to identify a subset of VF patients whose first rescue shock is likely to fail, making them candidates for a cardiopulmonary resuscitation (CPR)-first strategy.</AbstractText>After gaining institutional review board approval from all three institutions, we merged data from Los Angeles, Pittsburgh, and Royal Oak into a new cardiac arrest database. We used classification and regression tree (CART) analyses to build the model. We defined a failed first rescue shock as one in which there was no return of spontaneous circulation (ROSC); the postshock electrocardiographic (ECG) rhythm was VF, pulseless electrical activity (PEA), or asystole; or subsequent shocks were delivered (indicating that the first shock had failed).</AbstractText>The database contains 5,046 cases, of which 1,777 (35%) had VF as the initial ECG rhythm. Sufficient data were present for 748 cases. Using unwitnessed collapse, a response time of >6 minutes, and absence of bystander CPR (BCPR) on EMS arrival as predictors, 35 of 35 (100%, 95% confidence interval [CI] 100-91.4%) cases had failed first rescue shocks. Second shock failure was predicted in 162 of 164 (99%) cases.</AbstractText>Unwitnessed collapse, response time>6 minutes, and absence of BCPR may be useful in predicting which VF patients are likely to have failed first shocks and would thereby benefit from a CPR-first strategy. Stacked rescue shocks most often fail, and this outcome can also be predicted.</AbstractText> |
7,560 | Delay prior to calling 9-1-1 is associated with increased mortality after out-of-hospital cardiac arrest. | We sought to characterize the collapse-to-9-1-1 call interval, to evaluate the frequency of pre-9-1-1 delay, and to assess whether delay is associated with decreased survival after out-of-hospital cardiac arrest (OHCA).</AbstractText>This was a five-year prospective survey of bystanders to adult OHCA cases in which the victims were transported to seven local teaching hospitals in Michigan. Bystander data were obtained by telephone interview beginning two weeks after the event, and through review of emergency medical services (EMS) documents. Criteria for pre-9-1-1 delay were prospectively developed. Two paramedic reviewers were trained on these criteria and reviewed bystander and EMS data for each cardiac arrest case. Multivariate regression analysis was used to assess the independent impact of delay on survival. We collected common bystander and EMS OHCA demographics, as well as bystander description of events prior to the 9-1-1 call. Outcome was survival to hospital discharge.</AbstractText>During the study period we identified 1,004 OHCAs, for which 779 bystanders completed interviews. Of these interviews, 688 had adequate data for analysis. Raters showed moderate to strong agreement for a 15% subsample of cases. Of all cases, 330 (48%) were identified as having had pre-9-1-1 delay. Delay was less commonly associated with witnessed arrest (odds ratio [OR] 2.7; 95% confidence interval [CI] 2.0-3.7%) and public location (OR 1.57; 95% CI 1.1-2.2%). In a multivariate model, only initial-rhythm ventricular tachycardia/ventricular fibrillation was associated with improved survival (OR 2.28; 95% CI 1.3-4.1), and pre-9-1-1 delay was associated with decreased survival (OR 0.46; 95% CI 0.3-0.9%).</AbstractText>This method demonstrated that prehospital delay is common in OHCA and is associated with increased mortality. Measurement of pre-9-1-1 delay may improve precision of predictive models for OHCA survival.</AbstractText> |
7,561 | Long-term follow-up of patients with relatively high effective defibrillation threshold during cardioverter defibrillator implantation with endocardial leads. | We evaluated the 15-year outcome of patients with an implantable cardioverter defibrillator (ICD) and a relatively high defibrillation threshold (DFT).</AbstractText>After ICD implantation, patients were allocated to 3 groups: DFT 24-25 J (16 patients), effective defibrillation with 18-20 J (20 patients) and DFT <15 J (118 patients). An abbreviated DFT test was used during the implantation. The follow-up duration was 15.5 years.</AbstractText>There was no significant difference between the survivals of the 3 groups, with a mean survival of 7.30 +/- 4.51 years. In the ventricular fibrillation zone, 99.69, 100 and 100% of the episodes were successfully defibrillated in the 3 groups, respectively. In the ventricular tachycardia zone, 83.24, 92.86 and 95.39% of the episodes were terminated with pacing therapy. The small differences between the groups were not statistically significant. The testing method did not have an impact on survival or therapy success rate.</AbstractText>A 24-joule DFT with a 10-joule safety window is safe during 15 years of follow-up.</AbstractText>(c) 2008 S. Karger AG, Basel.</CopyrightInformation> |
7,562 | How much lung ventilation is obtained with only chest-compression CPR? | The objective of this 14-pig study was designed to determine the amount of lung ventilation obtainable by only rhythmic chest compression (100/min, 100 lbs). Tidal volume (TV), dead space (DS), and respiration rate (R) were measured with normal breathing and with rhythmic chest compression during ventricular fibrillation. The ratio of TV/DS was calculated in both cases. For normal breathing the ratio was 2.54 +/- 0.68; for chest compression breathing the ratio was 0.80 +/- 0.07. Minute alveolar ventilation (TV - DS)R was computed for both cases. With spontaneous breathing, the minute alveolar volume was 5.48 +/- 2.1 l/min. With only chest-compression breathing, the alveolar ventilation was -1.49 +/- 0.64 l/min. The negative minute alveolar volume and fractional ratio reveals that TV was less than the dead space indicating that chest-compression alone does not ventilate the lungs. |
7,563 | Elective and emergency defibrillation. | Defibrillation is the only effective treatment in cardiac arrest for ventricular fibrillation and pulseless ventricular tachycardia. This article aims to identify the need for defibrillation, both elective and emergency, and assist the nurse in understanding the evidence related to effective defibrillation (Nolan et al 2006). |
7,564 | Both Purkinje cells and left ventricular posteroseptal reentry contribute to the maintenance of ventricular fibrillation in open-chest dogs and swine: effects of catheter ablation and the ventricular cut-and-sew operation. | Radiofrequency catheter ablation (RFCA) targeting the left ventricular posteroseptum (LVPS) and posterior papillary muscle (PPM) terminates or prevents ventricular fibrillation (VF) in rabbit and dog hearts. However, whether the mechanism of VF maintenance is reentry or focal Purkinje firing is unclear.</AbstractText>In the present study the effects of RFCA (endocardial ablation of PPM+LVPS in 7 dogs and 7 swine), left ventricular anterolateral wall ablation (LVAL in 7 dogs), and the cut-and-sew operation (CSO: along the left ventricular posterior wall (LVPW) beside PPM in 7 swine) on VF inducibility were compared. (1) VF inducibility was decreased from 100+/-0% to 21.9+/-31.2% (p<0.0001) by PPM+LVPS endocardial ablation, but not by LVAL ablation in dogs. (2) LVPW CSO reduced VF inducibility (100+/-0% to 43.6+/-9.5%, p<0.0001) in swine. (3) In contrast to the canine Purkinje network, which is mostly localized to the subendocardium, the swine Purkinje network extends to the subepicardial layer with a higher density (p<0.001).</AbstractText>Both PPM+LVPS ablation (Purkinje destruction) in dogs and LVPW CSO (blocking reentry) in swine reduce VF inducibility, suggesting that in both species focal firing from the Purkinje network and reentry around the PPM contributes to the maintenance of VF.</AbstractText> |
7,565 | Circulating adiponectin levels in patients with atrial fibrillation. | Atrial fibrillation (AF) characterized by atrial remodeling occurs with obesity-related conditions. Adiponectin, an adipose tissue-derived hormone exerts beneficial effects on ventricular remodeling, so in the present study the potential association between circulating adiponectin levels and atrial remodeling in patients with AF was investigated.</AbstractText>The levels of plasma adiponectin, serum carboxy-terminal telopeptide of collagen type I (CITP), as a collagen type I degradation marker, and serum type III procollagen-N-peptide (PIIINP), as a collagen type III synthesis marker, were measured in 304 consecutive patients (162 paroxysmal AF, 46 persistent AF, 96 paroxysmal supra-ventricular tachycardia [controls]). Plasma adiponectin levels were significantly higher in patients with persistent AF than in those with paroxysmal AF or the control patients (p<0.05). Serum CITP levels, but not serum PIIINP levels, were higher in patients with persistent AF compared with the paroxysmal AF and control patients (p<0.05). In addition, there was a positive correlation between adiponectin levels and CITP levels in patients with persistent AF (r=0.39, p<0.005).</AbstractText>High plasma adiponectin levels are associated with the presence of persistent AF, which is accompanied by increased CITP levels. Thus, measurement of plasma adiponectin could be useful for assessment of AF.</AbstractText> |
7,566 | ECG-edit function in multidetector-row computed tomography coronary arteriography for patients with arrhythmias. | ECG-gating is necessary for cardiac computed tomography, but is not suitable for arrhythmias, so the aim of this study was to evaluate the usefulness of the ECG-edit function for this purpose.</AbstractText>Of 1,221 patients undergoing 64-row multidetector-row computed tomography coronary angiography (coronary MDCT), 123 patients (28 atrial fibrillation (Af), 39 premature atrial contractions (PAC), 42 premature ventricular contractions (PVC), 3 PAC + PVC, 10 sinus arrhythmias (SA), and a second-degree atrioventricular block (2 degrees AVB)) had arrhythmias necessitating the ECG-edit function. Short R-R interval was deleted and mid-diastolic phases were selected from the long R-R intervals using the "R+absolute time" method. In the present study, the reconstructed images were evaluated using a triple-grade scale A-C, representing excellent, acceptable, and unacceptable image quality. Image quality, categorized as A, B and C, respectively, was 50%, 36% and 14% for the 28 patients with Af; 56%, 36% and 8% for the 39 PAC patients, and 65%, 33% and 2% in the 42 PVC patients. None of the scans of the PAC + PVC, SA, and 2 degrees AVB patients was ranked as C.</AbstractText>The ECG-edit function is useful for reconstructing coronary MDCT images in many arrhythmias, and provides clinically acceptable images in most cases.</AbstractText> |
7,567 | Differences in ventricular vulnerability, serum enzyme activities, and electrolyte levels between male and female broilers. | Sudden death syndrome (SDS) is one of the most serious diseases of fast-growing broilers. The incidence of SDS may result from a decrease in ventricular function. The purpose of this study was to explore the mechanism of sexual difference in the sensitivity of broilers to SDS by measuring their ventricular vulnerability, serum enzyme activities, and serum electrolyte levels. Results were as follows. 1) Ventricular fibrillation thresholds induced by injection of KCl and by electrical stimulus of male broilers were both significantly lower than those of female broilers (P < 0.05), suggesting that the ventricular vulnerability of male broilers was higher than that of female broilers. 2) Serum lactate dehydrogenase and creatine kinase activities of male broilers were significantly higher than those of female broilers (P < 0.01), but there was not a significant difference in serum aspartate aminotransferase activity between male and female broilers. 3) No significant difference was observed in serum electrolyte levels of potassium, sodium, and chloride between males and females. From these results, we concluded that there is a significant difference between males and females in their ventricular vulnerability and serum enzyme activities, which may result in a higher sensitivity of male broilers to injury of the myocardium by stress and may further result in a sexual difference in sensitivity to SDS. |
7,568 | Prognostic value and temporal behavior of the planar QRS-T angle in patients with nonischemic cardiomyopathy. | The planar QRS-T angle can be easily obtained from standard 12-lead ECGs, but its predictive ability is not established. We sought to determine the predictive ability of the planar QRS-T angle in patients with nonischemic cardiomyopathy and to assess QRS-T angle behavior over time.</AbstractText>Baseline QRS-T angles from 455 patients in the Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial were measured. All patients had nonischemic cardiomyopathy, New York Heart Association class I to III heart failure, and nonsustained ventricular tachycardia or frequent ventricular ectopy. The primary end point (a composite of total mortality, appropriate implantable cardioverter-defibrillator shock, or resuscitated cardiac arrest) occurred in 25 of 172 patients (14.5%) with a QRS-T angle < or =90 degrees and in 72 of 283 patients (25.4%) with a QRS-T angle >90 degrees (hazard ratio, 1.93; 95% confidence interval, 1.23 to 3.05; P=0.002). A QRS-T angle >90 degrees remained a significant predictor of the primary end point (P=0.039) after adjustment for treatment group, age, gender, QRS duration, left bundle-branch block, left ventricular ejection fraction, New York Heart Association class III, atrial fibrillation, and diabetes mellitus. The secondary end point (total mortality) occurred in 17 of the 172 patients (9.9%) with a QRS-T angle < or =90 degrees and in 49 of the 283 patients (17.3%) with a QRS-T angle >90 degrees (hazard ratio, 1.79; 95% confidence interval, 1.03 to 3.10; P=0.016). A sample of 152 patients with multiple follow-up ECGs was analyzed to assess temporal QRS-T angle behavior. Changes in the QRS-T angle correlated with changes in left ventricular ejection fraction and QRS duration over time (P<0.001).</AbstractText>A planar QRS-T angle >90 degrees is a significant predictor of a composite end point of death, appropriate implantable cardioverter-defibrillator shock, or resuscitated cardiac arrest in nonpaced, mild to moderately symptomatic patients with nonischemic cardiomyopathy with frequent or complex ventricular ectopy. QRS-T angles changed predictably with left ventricular ejection fraction and QRS duration.</AbstractText> |
7,569 | Survival rate and factors associated with 1-month survival of witnessed out-of-hospital cardiac arrest of cardiac origin with ventricular fibrillation and pulseless ventricular tachycardia: the Utstein Osaka project. | We reassessed 1-month survival of patients with witnessed out-of-hospital cardiac arrest (OHCA) of cardiac origin with ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) in Osaka, Japan, and identified factors associated with 1-month survival using updated data from 1998 to 2004 collected based on the Utstein Style.</AbstractText>Using the Utstein Osaka Project database, we analyzed 1028 cases which met the following criteria: (1) patient age 18 years or older; (2) presumed cardiac origin based on the definition of the Utstein Style; (3) witnessed by citizens; (4) VF or pulseless VT at the time of arrival of the ambulance. The main outcome measure was survival at 1 month after collapse. Variables to develop a predictive model for 1-month survival were selected by stepwise logistic regression.</AbstractText>Survival at 1 month was 19.6%. Factors retained in the final logistic regression were age, sex, type of witness, and time interval from (a) ambulance call receipt to cardiopulmonary resuscitation (CPR) by the ambulance crew; (b) ambulance call to defibrillation; (c) CPR by the ambulance crew to hospital arrival. Area under the receiver-operating characteristic curve for the model developed with the six variables was 0.738 and Hosmer-Lemshow goodness-of-fit p-value was 0.94.</AbstractText>We successfully developed a model to estimate the probability of 1-month survival using variables easy to collect in the early phase of resuscitation, and this model would help physicians and family members predict the likelihood of 1-month survival of OHCA patients on admission.</AbstractText> |
7,570 | Post-resuscitation hemodynamics and relationship to the duration of ventricular fibrillation. | We have observed consistent hemodynamic patterns after restoration of spontaneous circulation (ROSC) after ventricular fibrillation (VF) cardiac arrest. We sought to characterize the time-course of these patterns, and to determine whether these differed based on duration of the VF insult.</AbstractText>We performed a retrospective review of data from a randomized animal experiment that was conducted in an AAALAC-approved animal laboratory. We used mixed-breed domestic swine of either sex. Animals were anesthetized and instrumented for continuous recording of ECG and blood pressures. VF was induced electrically and allowed to progress for various times ranging from brief (22s) to moderate (less than 3 min) to prolonged (3-10 min). All animals were initially shocked (150J) up to three times. If ROSC was not achieved on the three initial shocks, a standardized treatment protocol was followed. We defined cardiovascular collapse as a SBP<90 mmHg sustained for 1 min. For statistical purposes, we classified animals as having VF of <3 min, or >3 min duration. Data were analyzed with Fisher's exact test and survival analysis.</AbstractText>A hyperdynamic phase, consisting of very high-blood pressures and tachycardia, was seen in all animals immediately after ROSC. This lasts from 1 to 4 min. Post-resuscitation cardiovascular collapse occurred in 2/7 (29%) animals in the <3 min group and 13/14 in the >3 min group (93%) p=0.006. Onset of cardiovascular collapse was highly related to duration of VF (log-rank p=0.004).</AbstractText>There are two distinct phases of hemodynamic change after resuscitation of VF. The first phase is a brief hyperdynamic phase. The second phase is either stabilization or cardiovascular collapse. When VF is brief, blood pressures often return to normal without exogenous support. When VF was prolonged animals were rescued with exogenous pressor. Healthcare providers should be prepared to provide pressor support for patients having ROSC after prolonged VF.</AbstractText> |
7,571 | Drug-induced long QT syndrome in women: review of current evidence and remaining gaps. | Women are at an increased risk of drug-induced long QT syndrome (LQTS). This major cardiac adverse effect may lead to malignant polymorphic ventricular tachycardias, termed torsades de pointes, which may degenerate into ventricular fibrillation and cause sudden death.</AbstractText>This article reviews current evidence and remaining gaps in knowledge about drug-induced LQTS in women.</AbstractText>Using the search terms gender, sex, and sex differences in combination with cardiac electrophysiology, long QT syndrome, HERG, membrane transporters, and cytochromes, we conducted a systematic review of the available literature in the PubMed database. Relevant English- and French-language publications (to October 2007) on sex differences in LQTS were identified.</AbstractText>Clinical and experimental studies have reported that gonadal hormones play a role in sex-related differences of QT interval prolongation. Androgens may diminish drug effects on heart repolarization, and estrogens may facilitate arrhythmias. Furthermore, sex-related differences in the density of ion channels may partially explain this phenomenon. However, the magnitude of hormone-dependent differences observed in these studies remains very small compared with the large differences observed in clinical settings. Therefore, many scientists agree that the mechanisms responsible for sex-related differences in the risk of proarrhythmia from drugs remain largely undefined.</AbstractText>Other factors, such as sex-related modulation of drug disposition in situ, may fill the gaps in our understanding of the sex differences observed in drug-induced LQTS. We suggest that mechanisms such as the modulation of the pharmacokinetics of IKr (rapid component of the delayed rectifier potassium current) blockers, via modulation of intra- and extracellular concentrations, may be of major importance. Sex-specific changes in drug transport and metabolism will result in different plasma and intracellular levels acting along a dose-response effect on IKr block. Consequently, important hormone-dependent factors such as metabolic enzymes and membrane transporters need to be investigated in new basic research studies.</AbstractText> |
7,572 | Age at repair affects the very long-term outcome of sinus venosus defect. | Records of patients who had repair of sinus venosus defect (SVD) between 1970 and 2008 were reviewed to predict very long-term outcome.</AbstractText>Repairs occurred in 104 consecutive patients (51 men), aged 29 +/- 23 years (range, 1 to 70 years). Seven had isolated SVD and 97 had associated lesions that required concomitant operations. Five patients had preoperative arrhythmias; 24 (23%) were in New York Heart Association (NYHA) class III to V. Single-patch repair was done in 91 patients, caval translocation (Warden) in 7, and double-patch in 6.</AbstractText>Ten late deaths during 38 years of follow-up (mean, 15 +/- 20 years). Survival was 97% +/- 2% and 79% +/- 7% at 10 and 30 years. Thirty-one (29%) long-term survivors experienced 47 complications, including chronic/recurrent supraventricular tachycardia in 28, heart failure in 5, permanent pacing in 8, cerebrovascular accident in 3, and unrelated cardiac reoperation in 3. At 30 years, freedom from adverse cardiac events was 47% +/- 9%, from supraventricular tachycardia, 50% +/- 9%; from permanent pacing, 83 +/- 6%; and from cerebrovascular accident, 96% +/- 2%. Follow-up age was 42 +/- 23 years (range, 5 to 82 years); 74 patients (79%) were in NYHA class I, and 15 and 5 were in class II and III to IV, respectively. Baseline cardiac rhythm was sinus in 75 patients (84%), atrial fibrillation in 11 (12%), and paced in 8. Nine patients had moderate/severe pulmonary hypertension, and 8 had left ventricular dysfunction. Only older age at operation was associated with lower survival (p = 0.003), freedom from cardiac events (p = 0.001), supraventricular tachycardia (p = 0.009), and permanent pacing (p = 0.002). Repair before age 20 was associated with lower NYHA class at follow-up (p = 0.01).</AbstractText>SVD repair at an older age is associated with increased risk of late mortality, adverse cardiac events, and worse functional outcome. Repair during childhood is strongly advised.</AbstractText> |
7,573 | Restoration of sinus rhythm by the Maze procedure halts progression of tricuspid regurgitation after mitral surgery. | Tricuspid regurgitation (TR) is common in patients undergoing mitral valve surgery, and atrial fibrillation (AF) can cause progression of TR. This study examined the hypothesis that correction of AF with the Maze procedure can prevent the late progression of TR after mitral valve surgery.</AbstractText>We compared severity of TR in 33 patients (January 1, 1993, to January 1, 2003) who underwent concomitant Maze procedure plus mitral valve surgery and converted to normal sinus rhythm postoperatively with case-matched control patients who underwent mitral valve surgery alone and remained in AF postoperative. Matched variables were age, sex, diabetes mellitus, left ventricular ejection fraction, and hypertension. Preoperative TR grade was similar between groups (Maze 2.2 +/- 0.8 versus no-Maze 2.3 +/- 0.8, p = 0.67). Patients with permanent transvenous pacemakers, organic tricuspid valve disease, and prior tricuspid valve surgery were excluded from this comparison.</AbstractText>Before hospital dismissal, average TR grade improved to 1.9 +/- 0.9 in both groups; TR improved in 42% of patients in the Maze group and 36% of patients with preoperative AF and no Maze. At last follow-up, average TR grade remained stable at 1.9 +/- 0.9 in the Maze group (p = 0.078 versus preoperative) with TR progression in only 9% of patients (3 of 33). In contrast, TR grade worsened to 2.7 +/- 0.9 in the no-Maze group (p = 0.04 versus preoperative, p < 0.001 versus postoperative, p < 0.001 versus groups), and TR worsened in 45% of patients (15 of 33). In a multivariable model, performance of a Maze procedure was protective against the progression of TR.</AbstractText>Continued AF after mitral valve surgery can predispose a patient to progression of TR, and this progression is prevented in patients having successful concomitant Maze procedure.</AbstractText> |
7,574 | Usefulness of left atrial volume index to predict heart failure hospitalization and mortality in ambulatory patients with coronary heart disease and comparison to left ventricular ejection fraction (from the Heart and Soul Study). | The predictive value of left atrial (LA) dilatation in ambulatory adults with coronary artery disease is not known. It was hypothesized that echocardiographic LA volume index (LAVI) predicts heart failure (HF) hospitalization and mortality with similar statistical power as left ventricular ejection fraction (LVEF) in ambulatory adults with coronary artery disease. We measured LAVI in 935 adults without atrial fibrillation, atrial flutter, or significant mitral valve disease in the Heart and Soul Study. LAVI was calculated using the biplane method of disks. Outcomes included HF hospitalization and mortality. Logistic regression odds ratios (ORs) were calculated and adjusted for age, demographics, medical history, left ventricular mass, diastolic function, and LVEF. Mean LAVI was 32 +/- 11 ml/m2, and mean LVEF was 62 +/- 10%. Sixty-six patients (7%) had LAVI >50 ml/m2. There were 108 HF hospitalizations and 180 deaths at 4.3 years of follow-up. C statistics calculated as the area under the receiver-operator characteristic curve were the same (0.60) for LAVI and LVEF in predicting mortality. The unadjusted OR for HF hospitalization was 4.4 for LAVI >50 ml/m2 and 5.3 for LVEF <45% (p <0.001). In those with normal LVEF, the ORs for LAVI >50 ml/m2 were 5.2 for HF hospitalization (p <0.0001) and 2.5 for mortality (p = 0.006). After multivariate adjustment, LAVI >50 ml/m2 was predictive of HF hospitalization (OR 2.4, p = 0.02), and LAVI >40 ml/m2 was predictive of mortality (OR 1.9, p = 0.005). In conclusion, LAVI had similar predictability as LVEF for HF hospitalization and mortality in ambulatory adults with coronary artery disease. |
7,575 | Enhanced proinflammatory response of mononuclear cells to in vitro LPS-challenge in patients with ventricular fibrillation in the setting of acute myocardial infarction. | Ventricular fibrillation (VF) in the setting of acute myocardial infarction (AMI) is the leading cause of sudden cardiac death. A potential role of intrinsic, subclinical inflammatory states in patients suffering from ischemia-related VF has not been investigated yet. The aim of the present study was (i) to examine serum levels of proinflammatory markers in VF survivors and (ii) to evaluate basal and lipopolysaccharide (LPS)-stimulated interleukin-8-mRNA (IL-8-mRNA) levels in patients with and without VF complicating AMI.</AbstractText>Twenty-five patients with a history of VF during AMI and a control group of 25 AMI patients without VF were included. Blood samples were taken remote from AMI with a mean of 590 days. Circulating serum levels of IL-8, IL-6, soluble E-selectin (sE-selectin), tissue factor activity (TFA), tissue inhibitor of matrix-metalloproteinase-1 (TIMP-1) and matrix-metalloproteinase-9 (MMP-9) were measured. Mononuclear cells were isolated by density gradient centrifugation. The cells were stimulated with lipopolysaccharide (LPS) from Escherichia coli (700 ng/mL). IL-8-mRNA levels in mononuclear cells were determined by a colorimetric mRNA quantification assay.</AbstractText>Serum levels (median; range) of IL-8 (VF: 2.24 pg/mL; <0.10-19.3 pg/mL versus controls: 0.10 pg/mL; <0.10-7.7 pg/mL; p=0.014), IL-6 (VF: 0.68 pg/mL; <0.05-2.9 pg/mL versus controls: 0.23 pg/mL; <0.05-1.8 pg/mL; p=0.042) and TIMP-1 (VF: 229 ng/mL; 144-348 ng/mL versus controls: 186 ng/mL; 126-263 ng/mL; p=0.014) were significantly higher among patients with VF as compared to controls. Baseline IL-8-mRNA concentrations of blood mononuclear cells were significantly higher among patients with VF (257 amol/mL; 52-2672 amol/mL) as compared to patients without VF (37 amol/mL, 3.2-770 amol/mL; p<0.01). IL-8-mRNA levels after LPS-challenge were significantly higher among patients with VF (3503 amol/mL; 215-13,573 amol/mL) than in patients without VF (1003 amol/mL; 208-3386 amol/mL; p<0.01).</AbstractText>Circulating IL-8, IL-6, and TIMP-1 concentrations as well as IL-8-mRNA expression in mononuclear cells at baseline and after LPS-challenge are increased among patients with a history of VF in the setting of AMI as compared to patients without VF. These findings indicate an enhanced inflammatory response to a proinflammatory stimulus in VF survivors. The magnitude of this increased acute phase reactants may indicate a novel pathway of arrhythmogenesis in patients with AMI.</AbstractText> |
7,576 | [Therapeutic hypothermia in neurocritical patients]. | Induced hypothermia in neurocritical patients is one of the most promising neuroprotective therapies in the last decade. Unfortunately, the promising results obtained in experimental studies have had an unequal reflection in the different diseases that affect the neurocritical patient. The use of therapeutic hypothermia is clearly established in patients with neurological deterioration after cardiac arrest. On the contrary, its use in patients with traumatic brain injury is highly controversial. There is not enough evidence in stroke and hemorrhagic patients to support its use except in clinical trials. Nowadays, the greater understanding of the pathophysiology of secondary brain damage, the go od clinical results obtained in randomized clinical trials in patients with cerebral anoxia after ventricular fibrillation and the new cooling methods that have appeared have improved the interest of hypothermia in neurocritical patients. Induced hypothermia has a role in the intensive care unit. Critical care physicians should be familiar with the physiologic effects, current indications, techniques, and complications of induced hypothermia. This review elaborates on the clinical implications of hypothermia research in traumatic brain injury, anoxic, brain injury, stroke and intracerebral hemorrhage. |
7,577 | [Heart failure in outpatients: comorbidities and management by different specialists. The EPISERVE Study]. | The aim of the EPISERVE study was to investigate the clinical characteristics of heart failure in outpatients and its diagnostic and therapeutic management by cardiology, internal medicine and primary care specialists.</AbstractText>The study involved 507 physicians working in primary care (n=181, 36%), cardiology (n=172, 34%) or internal medicine (n=154, 30%) who treated 2249 consecutive outpatients with heart failure between June and November 2005.</AbstractText>The prevalence of heart failure was 2% in primary care, 17% in cardiology and 12% in internal medicine. Hypertension or coronary disease was the cause in more than 80% of cases. The prevalence of comorbidities was high: atrial fibrillation, 46%; diabetes, 38%; obesity, 64%; dyslipidemia, 60%; anemia, 27%; and renal failure, 7%. In 40% of cases, systolic function was preserved (i.e., left ventricular ejection fraction > or =45%). Echocardiographic and coronary angiographic studies were performed more frequently in patients seen in cardiology and in male patients. There were significant differences between men and women in pharmacologic treatment involving beta-blockers (55% vs. 44%, respectively; P< .001), diuretics (88% vs. 92%, respectively; P< .01) and statins (57% vs. 47%, respectively; P< .001). Only 20% of patients received the treatment recommended by clinical practice guidelines. The factors independently associated with appropriate treatment were being treated in cardiology, hypercholesterolemia, age and etiology.</AbstractText>The varied approaches of different specialists, the smaller effort put into diagnosis and therapy in women, and the low percentage of patients treated according to guidelines make it essential that an educational and multidisciplinary strategy should be developed for managing outpatients with heart failure.</AbstractText> |
7,578 | Sex difference and factors associated with outcome in patients with sustained ventricular arrhythmias. | To describe gender differences and factors of importance for outcome in patients referred for sustained ventricular arrhythmias.</AbstractText>Two hundred and fifty three patients took part in the survey, 126 (20 women) had sustained monomorphic ventricular tachycardia (VT) and 127 (31 women) had polymorphic VT/ventricular fibrillation. Ischemic heart disease was less common in women than in men (47 vs. 80%). At discharge, an ICD implant was similarly common in women (33%) and men (29%). One hundred and twenty five (65%) men and 37 (79%) women were alive at follow-up, p =0.08 (median follow-up 53 months). Independent predictors of long-term mortality were: 1) PVT/VF as the presenting arrhythmia, 2) a low ejection fraction, 3) increased QRS duration and 4) diabetes mellitus.</AbstractText>The lower proportion of women compared to men being referred for evaluation of sustained ventricular arrhythmias may contribute to the lower number of ICD implants in women. The long-term survival in women and men did not differ significantly.</AbstractText> |
7,579 | Role of extracorporeal circulation in the management of accidental deep hypothermia. | Deep hypothermia leading to cardiac arrest requires aggressive management for resuscitation. Various methods are available to rewarm the patient. We hereby present a case report where active resuscitation was carried out using cardiopulmonary bypass in a young female who was found unconscious with a core temperature of 26 degrees C. The relevant literature is also reviewed. |
7,580 | Rhythm control versus rate control for atrial fibrillation and heart failure. | It is common practice to restore and maintain sinus rhythm in patients with atrial fibrillation and heart failure. This approach is based in part on data indicating that atrial fibrillation is a predictor of death in patients with heart failure and suggesting that the suppression of atrial fibrillation may favorably affect the outcome. However, the benefits and risks of this approach have not been adequately studied.</AbstractText>We conducted a multicenter, randomized trial comparing the maintenance of sinus rhythm (rhythm control) with control of the ventricular rate (rate control) in patients with a left ventricular ejection fraction of 35% or less, symptoms of congestive heart failure, and a history of atrial fibrillation. The primary outcome was the time to death from cardiovascular causes.</AbstractText>A total of 1376 patients were enrolled (682 in the rhythm-control group and 694 in the rate-control group) and were followed for a mean of 37 months. Of these patients, 182 (27%) in the rhythm-control group died from cardiovascular causes, as compared with 175 (25%) in the rate-control group (hazard ratio in the rhythm-control group, 1.06; 95% confidence interval, 0.86 to 1.30; P=0.59 by the log-rank test). Secondary outcomes were similar in the two groups, including death from any cause (32% in the rhythm-control group and 33% in the rate-control group), stroke (3% and 4%, respectively), worsening heart failure (28% and 31%), and the composite of death from cardiovascular causes, stroke, or worsening heart failure (43% and 46%). There were also no significant differences favoring either strategy in any predefined subgroup.</AbstractText>In patients with atrial fibrillation and congestive heart failure, a routine strategy of rhythm control does not reduce the rate of death from cardiovascular causes, as compared with a rate-control strategy. (ClinicalTrials.gov number, NCT00597077.)</AbstractText>2008 Massachusetts Medical Society</CopyrightInformation> |
7,581 | [Ventricular tachyarrhythmias in patients with cardiomyopathy]. | The purpose of this study was to determine the number and distribution of cardiomyopathies as the aetiology of ventricular tachyarrhythmias among patients discharged from the Department of Cardiology, Rigshospitalet.</AbstractText>The study was a retrospective review of patients discharged with the diagnostic codes ventricular tachycardia, ventricular fibrillation or premature ventricular contractions with cardiomyopathy as the presumed aetiology. Patients discharged during a period of 6 years and 5 months were included in the study. The patients were characterized by disease, gender, age, previous cardiac arrest and treatment with implantable cardioverter-defibrillator (ICD).</AbstractText>993 patients were screened and 128 patients with cardiomyopathy were identified, corresponding to 13% of the screened patients. 58 (45%) of the patients had dilated cardiomyopathy (DCM), 57 (45%) patients had arrhythmogenic right ventricular cardiomyopathy (ARVC) and 13 (10%) had hypertrophic cardiomyopathy (HCM). The average age was 44 years for HCM, 41 years for ARVC and 58 years for DCM. The majority of the patients were male. ICD treatment was used in 95% of the patients with ARVC, 70% of the patients with HCM and 59% of the patients with DCM. Only 5 patients had previous cardiac arrest without reversible cause.</AbstractText>The study shows that cardiomyopathies are relatively frequent causes of ventricular tachyarrhythmias in patients discharged from a specialised cardiology department. Implantation of an ICD device has a central position in the treatment of patients with cardiomyopathy and ventricular tachyarrythmias and is primarily used as a prophylactic treatment.</AbstractText> |
7,582 | [Ventricular tachyarrhythmias. A retrospective analysis of etiology, demography and treatment]. | The aim of this study was to investigate the age, sex, etiology, frequency of implantable cardioverter-defibrillator (ICD) and previous cardiac arrest among patients discharged from the Department of Cardiology, Rigshospitalet (Copenhagen University Hospital), Denmark, due to ventricular tachyarrhythmias.</AbstractText>We conducted a retrospective review of 993 patients discharged from Rigshospitalet over 6 years and 5 months with the diagnostic codes ventricular tachycardia, ventricular fibrillation or premature ventricular contractions.</AbstractText>The population had an average age of 59 years (ranging 15-95 years) with a majority of males (76%). Among the patients with known etiology ischemic heart disease (60%), dilated cardiomyopathy (6%) and arrhythmogenic right ventricular cardiomyopathy (6%) were the most frequent. A substantial number of the patients (15%) had unknown etiology; 492 (50%) of the patients overall had an ICD implanted, the majority of whom had been categorized as having ventricular tachycardia (92%); 168 patients had previous cardiac arrest, 127 of whom did not have a potential reversible cause. Of this group 75 (59%) had an ICD implanted.</AbstractText>Ischemic heart disease is the most common cause of ventricular tachyarrhythmias. Approximately half the patients admitted with ventricular tachyarrhythmias had an ICD implanted, the majority of whom did not have previous cardiac arrest.</AbstractText> |
7,583 | The effect of aprotinin on risk of acute renal failure requiring dialysis after on-pump cardiac surgery. | The use of aprotinin in cardiac surgery to reduce perioperative bleeding and transfusion is controversial. We assessed the effect of aprotinin on the risk of acute renal failure in 423 patients who underwent on-pump cardiac surgery between January 1, 2005 and December 31, 2006. Of these 423 patients, 318 (75.2%) received aprotinin (median dose=3.0 million KIU, standard deviation=2.8 million KIU; interquartile range: 2 million KIU to 4 million KIU). Aprotinin was more likely to be used in patients who did not cease aspirin before surgery, in urgent or emergency surgery, who had impaired left ventricular function, a longer period of bypass and aortic cross-clamp time, and with both coronary artery bypass graft and valvular surgery performed. The overall incidence of acute renal failure requiring dialysis was 2.8%. The use of aprotinin was not associated with a reduction in transfusion nor an increased risk of renal failure requiring dialysis, atrial fibrillation, cerebrovascular accident or mortality in the univarate analyses. In the multivariate analysis, only preoperative serum creatinine concentration (odds ratio [OR] 1.06 per 10 micromol/l increment in creatinine, 95% confidence interval [CI]: 1.01 to 1.14, P=0.029) and urgency of the surgery (urgent vs. scheduled surgery: OR 12.8, CI: 2.3 to 70.8, P=0.004; emergency vs. scheduled surgery: OR 23.1, CI: 3.0 to 180.2, P=0.003) were significantly associated with an increased risk of acute renal failure requiring dialysis. The use of low-dose aprotinin did not significantly reduce perioperative transfusion requirements and was not a significant risk factor for acute renal failure requiring dialysis in our patients. |
7,584 | Etiology, pathophysiology, and treatment of atrial fibrillation: part 1. | Atrial fibrillation (AF) is associated with a higher incidence of mortality, stroke, and coronary events than is sinus rhythm. AF with a rapid ventricular rate may cause a tachycardia-related cardiomyopathy. Immediate direct-current cardioversion should be performed in patients with AF and acute myocardial infarction, chest pain due to myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous beta blockers, verapamil, or diltiazem may be given to immediately slow a very rapid ventricular rate in AF. An oral beta blocker, verapamil, or diltiazem should be used in persons with AF if a fast ventricular rate occurs at rest or during exercise despite digoxin. Amiodarone may be used in selected patients with symptomatic life-threatening AF refractory to other drugs. Digoxin should not be used to treat patients with paroxysmal AF. Nonpharmacologic therapies should be used in patients with symptomatic AF in whom a rapid ventricular rate cannot be slowed by drugs. This is part 1 of a 2-part review of the etiology, pathophysiology, and treatment of atrial fibrillation. The second part will be published in the subsequent issue of Cardiology in Review. |
7,585 | The Brugada type 1 electrocardiographic pattern is common among Filipinos. | To measure the prevalence of the Brugada type 1 ECG pattern in the general population in the Philippines. STUDY SETTING AND DESIGN: Sudden unexplained death syndrome is rare in the West but is common among Southeast Asians. Ventricular fibrillation is the terminal event. The Brugada type 1 electrocardiographic (ECG) pattern with J point and coved ST elevation in right precordial leads, is a marker for sudden unexplained death syndrome. Its prevalence in the general population is unknown. A cross-sectional nationwide survey was performed in the Philippines in 2003 using a stratified multistage sampling design covering all the regions and provinces in the country. ECGs were performed in all adults surveyed. The prevalences of the Brugada type 1 ECG pattern (coved type) and any type Brugada ECG pattern were determined.</AbstractText>The Brugada type 1 (coved) ECG pattern in the general population in the Philippines was found in 0.2% (95% Confidence Interval [CI] 0.03%-0.36%) of the population. Among males the prevalence was 0.3% (+/-0.1). The prevalence of any type Brugada ECG was 2% (95% CI 1.5%-2.6%).</AbstractText>The Brugada ECG pattern is common among Filipinos. There is a need to determine the risk of sudden death among individuals with this marker in the general population.</AbstractText> |
7,586 | Acoustic cardiographic recording during ventricular fibrillation. | This is the second case report in literature that describes the simultaneous acoustic cardiographic, electrocardiographic, and invasive hemodynamic events that occurred before, during and after ventricular fibrillation that was successfully cardioverted to sinus rhythm. The absence of heart sounds, which are linked to the lack of effective myocardial contractility, correlated well with invasive hemodynamic data, indicating the lack of perfusion during ventricular fibrillation. These observations, coupled with the challenges of pulse detection as a sign of adequate perfusion during resuscitation suggest that acoustic cardiography may be a potentially effective supplemental diagnostic tool during the resuscitation of malignant arrhythmias. |
7,587 | A manikin-based observational study on cardiopulmonary resuscitation skills at the Osaka Senri medical rally. | To examine the current status and problems of resuscitation management in Japan as demonstrated at the 2006 and 2007 Osaka Senri medical rallies.</AbstractText>Using manikins, the quality of resuscitation was evaluated in 33 teams that participated in the medical rallies. The challenge was to deliver defibrillation shocks for ventricular fibrillation; data were recorded using the Laerdal PC Skill Reporting System (Norway). The teams were first subjectively (visually) evaluated by a panel of judges and these evaluations were later reaffirmed using video records.</AbstractText>An approximately 30s delay was observed between the time of contact and initiation of chest compression in the teams that adopted the American Heart Association (AHA) method compared with those that adopted the European Resuscitation Council (ERC) method. Although the overall quality of chest compressions was very good, in several instances, the hand positions were inappropriate and complete chest recoil was not achieved. The left paddle was incorrectly positioned by all teams. Only 15.8% of the teams were able to deliver shocks with less than 10s of interruption between the chest compressions. Regarding interruption of chest compressions at confirmation of correct tracheal tube placement, among the eight teams that adopted the AHA method, pauses of more than 10s were confirmed in five (62.5%).</AbstractText>Significant differences in performance between the AHA and ERC methods were observed. The ERC guidelines were more rational and suitable in terms of actual application than the AHA guidelines.</AbstractText> |
7,588 | A national scheme for public access defibrillation in England and Wales: early results. | Automated external defibrillators (AEDs) operated by lay persons are used in the UK in a National Defibrillator Programme promoting public access defibrillation (PAD).</AbstractText>Two strategies are used: (1) Static AEDs installed permanently in busy public places operated by those working nearby. (2) Mobile AEDs operated by community first responders (CFRs) who travel to the casualty.</AbstractText>One thousand five hundred and thirty resuscitation attempts. With static AEDs, return of spontaneous circulation (ROSC) was achieved in 170/437 (39%) patients, hospital discharge in 113/437 (26%). With mobile AEDs, ROSC was achieved in 110/1093 (10%), hospital discharge in 32 (2.9%) (P<0.001 for both variables). More shocks were administered with static AEDS 347/437 (79%) than mobile AEDs 388/1093 (35.5%) P<0.001. Highly significant advantages existed for witnessed arrests, administration of shocks, bystander CPR before arrival of AED and short delays to start CPR and attach AED. These factors were more common with static AEDs. For CFRs, patients at home did less well than those at other locations for ROSC (P<0.001) and survival (P=.006). Patients at home were older, more arrests were unwitnessed, fewer shocks were given, delays to start CPR and attach electrodes were longer.</AbstractText>PAD is a highly effective strategy for patients with sudden cardiac arrest due to ventricular fibrillation who arrest in public places where AEDs are installed. Community responders who travel with an AED are less effective, but offer some prospect of resuscitation for many patients who would otherwise receive no treatment. Both strategies merit continuing development.</AbstractText> |
7,589 | Limits of conventional therapies after prolonged normovolemic cardiac arrest in swine. | Patients' outcomes after prolonged cardiac arrest are often grim. The aim of this study was to find the longest period of normovolemic, normothermic, cardiac arrest no-flow after which good neurologic outcome can be achieved with conventional therapies.</AbstractText>Swine (28-37 kg) were subjected to ventricular fibrillation cardiac arrest, after which they were randomized into groups with 13 min (n=6), 15 min (n=6), or 17 min (n=6) of untreated cardiac arrest followed by advanced life support (ALS) for 20 min (epinephrine 0.04 mg/kg every 3 min and vasopressin 0.4 IE/kg every 6 min, no defibrillation attempts), followed by cardiopulmonary bypass (CPB). To mimic an unresuscitable situation after prolonged cardiac arrest, CPB was initiated 20 min after the start of resuscitation, followed by defibrillation attempts. Therapeutic mild hypothermia was applied for 20 h and a final neurologic evaluation (neurologic deficit score, NDS; overall performance category, OPC) was done after 9 days.</AbstractText>In the 13-min group, restoration of spontaneous circulation (ROSC) was achieved in five of six swine, four of which survived to day 9, and all had favorable neurologic outcomes [one swine OPC 1, three swine OPC 2, NDS 15% (IQR 6-21)]. In the 15- and 17-min groups, ROSC was achieved in three of six and two of six swine, respectively, one survived to day 9 with OPC 3 in each group, and NDS values were 45 and 58%, respectively (Kruskal-Wallis test for OPC, p=0.048).</AbstractText>In our model, the limit of normovolemic, normothermic, cardiac arrest no-flow time, followed by ACLS, CPB, and prolonged mild hypothermia, seems to be 13 min.</AbstractText> |
7,590 | [Out-of-hospital sudden cardiac arrest in the population of adults in Szczecin, years 2002-2003]. | Out-of-hospital cardiac arrest, with its high fatality rate, is a significant public health issue.</AbstractText>The survival of 421 patients with out-of-hospital cardiac arrest, who after the resuscitation were admitted to intensive care units in Szczecin in 2002-2003, was investigated. The outcome was analysed at two points of survival: hospital admission and hospital discharge. All data were computed with Microsoft Excel for Windows and were analysed according the Utstein style template.</AbstractText>In the resuscitated group, 326 patients had a cardiac aetiology of the arrest. Ventricular fibrillation (VF) as initial rhythm was observed more frequently. The survival was strictly associated with early defibrillation. Patients with VF as an initial rhythm had an almost four times higher chance of being successfully resuscitated and discharged alive. A total of 42 patients were discharge alive, most of them in good general condition, without any neurological defects.</AbstractText>The overall mortality rate was high. The outcome of out-of-hospital resuscitation in the city of Szczecin is still unsatisfactory. The results of the present study indicate that the rate of bystander resuscitation should be increased. The low number of resuscitations attempts by laypersons indicates that there is an urgent need to promote better pre-hospital cardiopulmonary resuscitation.</AbstractText> |
7,591 | Analyzing the electrophysiological effects of local epicardial temperature in experimental studies with isolated hearts. | As a result of their modulating effects upon myocardial electrophysiology, both hypo- and hyperthermia can be used to study the mechanisms that generate or sustain cardiac arrhythmias. The present study describes an original electrode developed with thick-film technology and capable of controlling regional temperature variations in the epicardium while simultaneously registering its electrical activity. In this way, it is possible to measure electrophysiological parameters of the heart at different temperatures. The results obtained with this device in a study with isolated and perfused rabbit hearts are reported. An exploration has been made of the effects of local temperature changes upon the electrophysiological parameters implicated in myocardial conduction. Likewise, an analysis has been made of the influence of local temperature upon ventricular fibrillation activation frequency. It is concluded that both regional hypo- and hyperthermia exert reversible and opposite effects upon myocardial refractoriness and conduction velocity in the altered zone. The ventricular activation wavelength determined during constant pacing at 250 ms cycles is not significantly modified, however. During ventricular fibrillation, the changes in the fibrillatory frequency do not seem to be transmitted to normal temperature zones. |
7,592 | Intravenous magnesium for cardiac arrhythmias: jack of all trades. | Intravenous magnesium has been used to prevent and treat many different types of cardiac arrhythmia. It has diverse electrophysiological actions on the conduction system of the heart; including prolonging sinus node recovery time, and reducing automaticity, atrioventricular nodal conduction, antegrade and retrograde conduction over an accessory pathway, and His-ventricular conduction. Intravenous magnesium can also homogenise transmural ventricular repolarisation. Because of its unique and diverse electrophysiological actions, intravenous magnesium has been reported to be useful in preventing atrial fibrillation and ventricular arrhythmias after cardiac and thoracic surgery; in reducing the ventricular response in acute onset atrial fibrillation, including for patients with Wolff-Parkinson-White syndrome; in the treatment of digoxin induced supraventricular and ventricular arrhythmias, multifocal atrial tachycardia, and polymorphic ventricular tachycardia or ventricular fibrillation from drug overdoses. Intravenous magnesium is, however, not useful in monomorphic ventricular tachycardia and shock-resistant ventricular fibrillation. Large randomised controlled studies are needed to confirm whether intravenous magnesium can improve patient centre outcomes in different cardiac arrhythmias. |
7,593 | Effect of chest compressions only during experimental basic life support on alveolar collapse and recruitment. | The importance of ventilatory support during cardiac arrest and basic life support is controversial. This experimental study used dynamic computed tomography (CT) to assess the effects of chest compressions only during cardiopulmonary resuscitation (CCO-CPR) on alveolar recruitment and haemodynamic parameters in porcine model of ventricular fibrillation.</AbstractText>Twelve anaesthetized pigs (26+/-1 kg) were randomly assigned to one of the following groups: (1) intermittent positive pressure ventilation (IPPV) both during basic life support and advanced cardiac life support, or (2) CCO during basic life support and IPPV during advanced cardiac life support. Measurements were acquired at baseline prior to cardiac arrest, during basic life support, during advanced life support, and after return of spontaneous circulation (ROSC), as follows: dynamic CT series, arterial and central venous pressures, blood gases, and regional organ blood flow. The ventilated and atelectatic lung area was quantified from dynamic CT images. Differences between groups were analyzed using the Kruskal-Wallis test, and a p<0.05 was considered statistically significant.</AbstractText>IPPV was associated with cyclic alveolar recruitment and de-recruitment. Compared with controls, the CCO-CPR group had a significantly larger mean fractional area of atelectasis (p=0.009), and significantly lower PaO2 (p=0.002) and mean arterial pressure (p=0.023). The increase in mean atelectatic lung area observed during basic life support in the CCO-CPR group remained clinically relevant throughout the subsequent advanced cardiac life support period and following ROSC, and was associated with prolonged impaired haemodynamics. No inter-group differences in myocardial and cerebral blood flow were observed.</AbstractText>A lack of ventilation during basic life support is associated with excessive atelectasis, arterial hypoxaemia and compromised CPR haemodynamics. Moreover, these detrimental effects remain evident even after restoration of IPPV.</AbstractText> |
7,594 | Shock outcome prediction before and after CPR: a comparative study of manual and automated active compression-decompression CPR. | We report on a study designed to compare the relative efficacy of manual CPR (M-CPR) and automated mechanical CPR (ACD-CPR) provided by an active compression-decompression (ACD) device. The ECG signals of out-of-hospital cardiac arrest patients of cardiac aetiology were analysed just prior to, and immediately after, cardiopulmonary resuscitation (CPR) to assess the likelihood of successful defibrillation at these time points. The cardioversion outcome prediction (COP) measure previously developed by our group was used to quantify the probability of return of spontaneous circulation (ROSC) after counter-shock and was used as a measure of the efficacy of CPR. An initial validation study using COP to predict shock outcome from the patient data set resulted in a performance of 60% specificity achieved at 100% sensitivity on a blind test of the data. This is comparable with previous studies and provided confidence in the robustness of the technique across hardware platforms. Significantly, the COP marker also displayed an ability to stratify according to outcomes: asystole, ventricular fibrillation (VF), pulseless electrical activity (PEA), normal sinus rhythm (NSR). We then used the validated COP marker to analyse the ECG data record just prior to and immediately after the chest compression segments. This was initially performed for 87 CPR segments where VF was both the pre- and post-CPR waveform. An increase in the mean COP values was found for both CPR types. A signed rank sum test found the increase due to manual CPR not to be significant (p>0.05) whereas the automated CPR was found to be significant (p<0.05). This increase was larger for the automated CPR (1.26, p=0.024) than for the manual CPR (0.99, p=0.124). These results indicate that the application of CPR does indeed provide beneficial preparation of the heart prior to defibrillation therapy whether manual or automated CPR is applied. The COP marker shows promise as a definitive, quantitative determinant of the immediate positive effect of both types of CPR regardless of the details of use. In work of a more exploratory nature we then used the validated COP marker to analyse the ECG pre- and post-CPR for all rhythm types (212 traces). We show a significant increase in the COP measure (p<0.001 in both cases) as indicated by a shift in the median COP marker distribution values. This increase was more pronounced for automated ACD-CPR than for manual CPR. However, a detailed statistical analysis carried out between the groups adjusted for pre-CPR value showed no significant difference between the two methods of CPR (p=0.20). Similarly, adjusting for length of CPR showed no significant difference between the groups. Secondary, subgroup analysis of the ECG according to the length of time for which CPR was performed showed that both types of CPR led to an increase in the likelihood of successful defibrillation after increasing durations of CPR, however results were less reliable after longer periods of continuous CPR. |
7,595 | Low levels of cellular omega-3 increase the risk of ventricular fibrillation during the acute ischaemic phase of a myocardial infarction. | Animal studies have demonstrated evidence of an anti-arrhythmic effect of marine n-3 fatty acids (FAs). In humans the same mechanism may explain the observed reduction in sudden cardiac death (SCD) associated with intake of fish. Whether high levels of n-3 FAs could protect against ventricular fibrillation (VF) during the acute ischaemic phase of a myocardial infarction (MI) is, however, not known.</AbstractText>We measured red blood cell content of eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA) expressed as a percentage of total FAs (the omega-3 index) at admission in 460 patients hospitalised with an acute coronary syndrome. Out of 265 patients suffering their first MI, 10 (cases) experienced an episode of VF during the initial 6h of symptom onset. The omega-3 index of these patients was compared to that of 185 first-MI patients (controls) free of VF for at least 30 days post-admission.</AbstractText>The median value of the omega-3 index in the VF cases was 4.88% as compared to 6.08% in the controls (p=0.013). After adjustment for age, sex, ejection fraction, high-sensitivity C-reactive protein, use of beta-blocker, differences of infarct characteristics and previous angina pectoris, a 1% increase of the omega-3 index was associated with a 48% reduction in risk of VF (odds ratio (OR) 0.52, 95% confidence interval (CI) 0.28-0.96; p=0.037).</AbstractText>Our study supports an anti-arrhythmic effect of n-3 FAs through their incorporation into myocardial cell membranes, reducing the risk of VF during ischaemia.</AbstractText> |
7,596 | Recurrent ventricular fibrillation during advanced life support care of patients with prehospital cardiac arrest. | The response of recurrent episodes of ventricular fibrillation (VF) to defibrillation shocks has not been systematically studied. We analyzed outcomes from countershocks delivered for VF during advanced life support (ALS) care of patients with out-of-hospital cardiac arrest.</AbstractText>Cohort of patients with prehospital cardiac arrest presenting with VF, treated by ALS ambulance staff following ERC Guidelines 2000. Biphasic defibrillators provided shocks increasing from 200 to 360J. Recorded signals were analyzed to determine, for each shock, if VF was terminated and if a sustained organized rhythm was restored within 60s.</AbstractText>In 465 of the 467 patients enrolled, the initial VF episode was terminated within three shocks: 92%, 61%, and 83% responded to 200J first, 200J second and 360J third shocks, respectively. VF recurred in 48% of patients within 2min of the first episode, and in 74% sometime during prehospital care. In the 175 patients experiencing five or more VF episodes, single shock VF termination dropped from the first to the fifth episode (90-80%, p<0.001) without change in transthoracic impedance, yet the proportion returning to organized rhythms increased (11-42%, p<0.0001).</AbstractText>Repeated refibrillation is common in patients with VF cardiac arrest. The likelihood of countershocks to terminate VF declines for repeated episodes of VF, yet shocks that terminate these episodes result increasingly in a sustained organized rhythm.</AbstractText> |
7,597 | Intracellular calcium dynamics and acetylcholine-induced triggered activity in the pulmonary veins of dogs with pacing-induced heart failure. | Heart failure increases autonomic nerve activities and changes intracellular calcium (Ca(i)) dynamics.</AbstractText>The purpose of this study was to investigate the hypothesis that abnormal Ca(i) dynamics are responsible for triggered activity in the pulmonary veins (PVs) during acetylcholine infusion in a canine model of heart failure.</AbstractText>Simultaneous optical mapping of Ca(i) and membrane potential was performed in isolated Langendorff-perfused PV-left atrial (LA) preparations from nine dogs with ventricular pacing-induced heart failure. Mapping was performed at baseline, during acetylcholine (1 micromol/L) infusion (N = 9), and during thapsigargin and ryanodine infusion (N = 6).</AbstractText>Acetylcholine abbreviated the action potential. In four tissues, long pauses were followed by elevated diastolic Ca(i), late phase 3 early afterdepolarizations, and atrial fibrillation (AF). The incidence of PV focal discharges during AF was increased by acetylcholine from 2.4 +/- 0.6 beats/s (N = 4) to 6.5 +/- 2.2 beats/s (N = 8; P = .003). PV focal discharge and PV-LA microreentry coexisted in 6 of 9 preparations. The spatial distribution of dominant frequency demonstrated a focal source pattern, with the highest dominant frequency areas colocalized with PV focal discharge sites in 35 (95%) of 37 cholinergic AF episodes (N = 8). Thapsigargin and ryanodine infusion eliminated focal discharges in 6 of 6 preparations and suppressed the inducibility of AF in 4 of 6 preparations. PVs with focal discharge have higher densities of parasympathetic nerves than do PVs without focal discharges (P = .01), and periodic acid-Schiff (PAS)-positive cells were present at the focal discharge sites.</AbstractText>Ca(i) dynamics are important in promoting triggered activity during acetylcholine infusion in PVs from pacing-induced heart failure. PV focal discharge sites have PAS-positive cells and high densities of parasympathetic nerves.</AbstractText> |
7,598 | Mild therapeutic hypothermia shortens intensive care unit stay of survivors after out-of-hospital cardiac arrest compared to historical controls. | Persistent coma is a common finding after cardiac arrest and has profound ethical and economic implications. Evidence suggests that therapeutic hypothermia improves neurological outcome in these patients. In this analysis, we investigate whether therapeutic hypothermia influences the length of intensive care unit (ICU) stay and ventilator time in patients surviving out-of-hospital cardiac arrest.</AbstractText>A prospective observational study with historical controls was conducted at our medical ICU. Fifty-two consecutive patients (median age 62.6 years, 43 males, 34 ventricular fibrillation) submitted to therapeutic hypothermia after out-of-hospital cardiac arrest were included. They were compared with a historical cohort (n = 74, median age 63.8 years, 53 males, 43 ventricular fibrillation) treated in the era prior to hypothermia treatment. All patients received the same standard of care. Neurological outcome was assessed using the Pittsburgh cerebral performance category (CPC) score. Univariate analyses and multiple regression models were used.</AbstractText>In survivors, therapeutic hypothermia and baseline disease severity (Acute Physiology and Chronic Health Evaluation II [APACHE II] score) were both found to significantly influence ICU stay and ventilator time (all P < 0.01). ICU stay was shorter in survivors receiving therapeutic hypothermia (median 14 days [interquartile range (IQR) 8 to 26] versus 21 days [IQR 15 to 30] in the control group; P = 0.017). ICU length of stay and time on ventilator were prolonged in patients with CPC 3 or 4 compared with patients with CPC 1 or 2 (P = 0.003 and P = 0.034, respectively). Kaplan-Meier analysis showed improved probability for 1-year survival in the hypothermia group compared with the controls (log-rank test P = 0.013).</AbstractText>Therapeutic hypothermia was found to significantly shorten ICU stay and time of mechanical ventilation in survivors after out-of-hospital cardiac arrest. Moreover, profound improvements in both neurological outcome and 1-year survival were observed.</AbstractText> |
7,599 | Sudden death in a young man with catecholaminergic polymorphic ventricular tachycardia and paroxysmal atrial fibrillation. | Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a familial condition that presents with exercise-induced syncope or sudden death in children or young adults. In most cases the disease is caused by a mutation in the cardiac ryanodine receptor (RyR2) gene. Current evidence suggests that primary therapy for CPVT is beta blockade and implantable cardioverter defibrillator (ICD) placement. There is a recent report of a patient with CPVT who died despite appropriate ICD therapies, and we report a similar case. Our patient died after probably initially receiving inappropriate ICD shocks for atrial fibrillation. We recommend that utmost efforts should be made to prevent shocks including repeated exercise testing to confirm suppression of PVT. |
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